Construction Systems: Prestressed Concrete PDF

03 – Construction Systems Alternative Building Construction Systems  AR413/S – Building Technology 5 AUTHORSHIP AND DISCLAIMER This work is prepared and consolidated by Ar. Noel T. Amor, Jr. Design...

03 – Construction Systems Alternative Building Construction Systems  AR413/S – Building Technology 5 AUTHORSHIP AND DISCLAIMER This work is prepared and consolidated by Ar. Noel T. Amor, Jr. Designed for UM-CAFAE Bachelor of Science in Architecture Program. For questions and corrections, contact the author at [email protected].  CONSTRUCTION SYSTEMS: PRESTRESSED CONCRETE Prepared by: Ar. Ken Benjamin T. Camao Designed for UM-CAFAE Bachelor of Science in Architecture Program REINFORCED CONCRETE Overview on Reinforced Concrete: ❑ Concrete is a material that is strong in compression, but weak in tension. ❑ Steel is strong in tension. ❑ Reinforced Concrete uses concrete to resist compression and to hold bars in position and uses steel to resist tension. ❑ Tensile strength of concrete is neglected. ❑ Reinforced Concrete beams allows crack under service load. REINFORCED CONCRETE Overview on Reinforced Concrete: ❑ In ordinary reinforced concrete, the Beam supports a load by developing compressive stresses at the top, but since the concrete cannot resist the tension at the bottom, it cracks. ❑ Reinforcing steel bars are placed within this tension zone to resist the tension and control the cracking. PRESTRESSED CONCRETE Even without a load, the ordinary concrete beam must carry its own weight. Reinforced Concrete An upward force is created which in effect relieves the beam of having to carry its own weight. Prestressed Concrete PRESTRESSED CONCRETE What is a Prestressed Concrete? Definition (1): Prestress is defined as a method of applying pre- compression to control the stresses resulting due to external loads below the neutral axis of the beam tension developed due to external loads which is more than the permissible limits of the plain concrete. Prestressed concrete is a method of overcoming concrete’s natural weakness in tension. PRESTRESSED CONCRETE What is a Prestressed Concrete? Definition (2): Pre-stressed concrete is a form of reinforced concrete that builds in compressive stresses during construction to oppose those found when in use. It is a combination of steel and concrete that takes advantages of the strength of each material. PRESTRESSED CONCRETE What is a Prestressed Concrete? Definition (3): Involving the application of forces to bend and compress a concrete element in order to counteract bending which comes from the structural load. The force applied is the tensioning of stretching of the steel component which usually in the form of high tensile strands, wires or bars. PRESTRESSED CONCRETE Principles of Prestressed Concrete Pre-stressing is a method in which compression force is applied to the reinforced concrete section. ❑ Pre-stressing tendons (generally of high tensile steel cable or rods) are used to provide a clamping load which produces a compressive stress that balances the tensile stress that the concrete compression member would otherwise experience due to a bending load. PRESTRESSED CONCRETE Principles of Prestressed Concrete ❑ The effect of pre-stressing is to reduce the tensile stress in the section to the point until the tensile stress is below the cracking stress. Thus, the concrete does not crack. ❑ It is then possible to treat concrete as an elastic material. PRESTRESSED CONCRETE Principles of Prestressed Concrete ❑ The concrete can be visualized to have two compressive force. ❑ Internal pre-stressing force ❑ External force PRESTRESSED CONCRETE Cement: Materials for ❑ ❑ Ordinary Portland cement Portland slag cement Prestressed ❑ ❑ Rapid hardening Portland cement High strength ordinary Portland cement Concrete Concrete: Member ❑ Prestressed concrete requires high strength concrete, which has high compressive strength comparatively higher tensile strength than ordinary concrete. ❑ The concrete as a material should be composed of gravels, crushed stones, sand, and cement. ❑ In prestressed concrete, minimum grade of concrete used in M20. Steel: ❑ High tensile steel, tendons and strands. ❑ In prestressed concrete, high tensile steel with tensile strength around 2000MPa is required. ❑ The steel should be in accordance with IS: 1343-1980 prestressed concrete design. PRESTRESSED CONCRETE Forms of Strands – Two, three or seven wires are wound to form a pre- Pre-stressing stressing strand. Steel: Wire - Pre-stressing wire is a single unit made of steel. Bars – A tendon can be made up of a Tendons – A group of strands or wires are single steel bar. The diameter of a bar is much larger than that of a wire. wound to form a pre-stressing tendon. PRESTRESSED CONCRETE How do we Pre-stress a material? 1 2 3 4 MECHANICAL HYDRAULIC ELECTRICAL CHEMICAL DEVICES DEVICES DEVICES DEVICES PRESTRESSED CONCRETE 1 MECHANICAL DEVICES The mechanical devices generally used include weights with or without lever transmission, geared transmission in conjunction with pulley blocks, screw jacks with or without gear devices and wire-winding machines. These devices are employed mainly for prestressing structural concrete components produced on a mass scale in factory. PRESTRESSED CONCRETE 2 HYDRAULIC DEVICES These are the simplest means of producing large prestressing force, extensively used as tensioning devices. PRESTRESSED CONCRETE 3 The wires are electrically heated and anchored before placing the concrete in the mould. This method is often referred to as thermo-prestressing and used for ELECTRICAL tensioning of steel wires and deformed bars. DEVICES PRESTRESSED CONCRETE 4 CHEMICAL DEVICES Expanding cements are used and the degree of expansion is controlled by varying the curing condition. Since expansive action of cement. PRESTRESSED CONCRETE 4 CHEMICAL DEVICES Expanding cement, also known as expansive cement, is a kind of Portland cement that produces slight volume expansion during the hydration and setting process PRESTRESSED CONCRETE Prestressed Concrete: Methods There are two basic methods of applying pre-stress to a concrete member: Pre-tensioning: A method of prestressing concrete in which the tendons are tensioned before the concrete is placed. In this method, the concrete is introduced by bond between steel and concrete. Post-tensioning: A method of prestressing concrete by tensioning the tendons against hardened concrete. PRESTRESSED CONCRETE Prestressed Concrete: Methods PRE-TENSION & POST-TENSION These two methods mainly differs in the method of stressing their components. A difference in the construction sequence and stress application. PRESTRESSED CONCRETE Prestressed Concrete: Methods PRE-TENSION & POST-TENSION ❑ Pre-tensioned Concrete is usually fabricated away from the job site in a pre-stressing plant. ❑ Post-tensioned Concrete the application of stressing forces to the structure is done at the job site. PRESTRESSED CONCRETE Pre-stressed Concrete: Methods PRE-TENSION & POST-TENSION before after “PRE-” “POST-” Pre-tension Prestressed Concrete The beams or elements are constructed on a stressing bed and stranded cable is place between two buttresses anchored to a stressing bed which holds the force in stretched cables. Pre-tension Prestressed Concrete After stretching the steel with hydraulic jacks, concrete is placed in forms around the cables and allowed to harden. When the concrete reaches its sufficient strength, the pre-stress force is transferred to the concrete by bond when the steel strand at the ends of the beam is cut loose from buttresses. PRESTRESSED CONCRETE Pre-Tensioning Methods 1 2 3 APPLYING CASTING OF TRANSFERRING TENSION TO CONCRETE OF PRE-STRESS TENDONS TENSILE STRUCTURE Stages of Pre-tensioning a Prestressed Concrete In Pre-tension, the tendon and reinforcements are positioned in the beam mould. The tendon 1 are then tensioned to about 70% of their ultimate strength against some abutments before the concrete is placed. APPLYING TENSION TO TENDONS TENSILE STRUCTURE Stages of Pre-tensioning a Prestressed Concrete Concrete is cast into the beam mould and 2 allowed to cure to the required initial strength. CASTING OF CONCRETE TENSILE STRUCTURE Stages of Pre-tensioning a Prestressed Concrete 3 When the concrete has cured, the stressing force is released and the tendons anchor t TRANSFERRING OF PRE-STRESS TENSILE STRUCTURE Stages of Pre-tensioning a Prestressed Concrete The tendon tries to shrink back to the initial length but the concrete resists it through the 3 bond between them, thus, compression force is induced in concrete. TRANSFERRING OF PRE-STRESS Post-tension Prestressed Concrete In post-tensioning the steel is stretched after the concrete hardens. Unlike pre-tensioning work, post-tensioning is usually carried out at the project site. In the case of post-tensioning, a duct is placed into the concrete structure. Post-tension Prestressed Concrete Another technique for reinforcing concrete members. Commonly, metal or plastic ducts are placed inside the concrete before casting. This can be done either as pre-cast or cast-in-place. PRESTRESSED CONCRETE Post-Tensioning Methods 1 2 3 CASTING OF TENSIONING OF ANCHORING THE CONCRETE TENDONS TENDON AT THE STRETCHING END PRESTRESSED CONCRETE Stages of Post-tensioning a Prestressed Concrete Steel cables inside plastic ducts or sleeves are positioned in the forms before concrete is 1 placed. Afterwards, once the concrete has gained strength, the cables are pulled tight and anchored against the outer edges of concrete. CASTING OF CONCRETE PRESTRESSED CONCRETE Stages of Post-tensioning a Prestressed Concrete After the concrete hardens, the tendons placed 2 inside the duct are anchored against the concrete and then tensioned to about 70% of their ultimate strength.. TENSIONING OF TENDONS PRESTRESSED CONCRETE Stages of Post-tensioning a Prestressed Concrete The excess ends of tendons are then cut away and the wedges are inserted into the end 3 anchorages and the tensioning force on the tendons is released. ANCHORING THE TENDON AT THE STRETCHING END Grout is then pumped into the ducts to protect the tendons. PRESTRESSED CONCRETE What are the advantages and disadvantages of Prestressed Concrete? 1 2 3 4 COST FAST CONSTRUCTION SAFETY AESTHETICS EFFICIENCY SCHEDULE PRESTRESSED CONCRETE Prestressed Concrete: Advantages ❑ Take full advantages of high strength concrete and high strength steel. ❑ Need less materials. ❑ Smaller and lighter structure. ❑ No cracks. ❑ Use the entire section to resist the load. ❑ Better corrosion resistance. ❑ Good for water tanks and nuclear plant. PRESTRESSED CONCRETE Prestressed Concrete: Advantages ❑ Very effective for deflection control due to better shear resistance. ❑ Lower construction cost. ❑ Thinner slabs, which are especially important in the high-rise buildings where floor thickness savings can translate into additional floors for the same or lower cost. PRESTRESSED CONCRETE Prestressed Concrete: Advantages ❑ Fewer joints since the distance that can be spanned by post-tensioned slabs exceeds that of reinforced construction with the same thickness. ❑ Longer span lengths increase the usable unencumbered floor space in buildings and parking structures. ❑ Fewer joints lead to lower maintenance cost over the design life of the structure, since joints are the major focus of weakness in concrete buildings. PRESTRESSED CONCRETE Prestressed Concrete: Disadvantages ❑ Need higher quality materials ❑ More complex technically ❑ More expensive ❑ Harder to re-cycle ❑ The major problem with prestressed concrete is that it needs specialized construction machineries like jacks, anchorage, etc. PRESTRESSED CONCRETE Prestressed Concrete: Disadvantages ❑ Advanced technical knowledge and strict supervision is very important. ❑ For concrete pre-stressing, high tensile reinforcement bars are needed which costs greater that generally used steel reinforcement bars. ❑ Highly skilled labor is needed for pre-stressed concrete construction. PRESTRESSED CONCRETE Prestressed Concrete: Common Application ❑ Bridges ❑ Slabs in buildings ❑ Water Tank ❑ Concrete Pile ❑ Thin Shell Structures ❑ Offshore Platform ❑ Nuclear Power Plant ❑ Repair and Rehabilitations PRESTRESSED CONCRETE Prestressed Concrete: Common Application PRESTRESSED CONCRETE Prestressed Concrete: Common Application  CONSTRUCTION SYSTEMS: COMPOSITE CONSTRUCTION Prepared by: Ar. Raysnil R. Lumpay Designed for UM-CAFAE Bachelor of Science in Architecture Program COMPOSITE CONSTRUCTION What is a Composite Construction? Definition (1): Composite construction occurs when two (2) different materials are bonded so securely that they function as a single structural unit. This interaction is known as composite action. Benefits of Composite Construction Speed of Construction Performance Value COMPOSITE CONSTRUCTION In other words; Concrete is strong in compression, while steel excels in tension. By combining these materials, their strengths can be utilized for a highly efficient and lightweight design. The reduced self-weight of composite elements also reduces the forces in supporting elements, including the foundations.  Composite Materials Scope of Composite Beams Composite Composite Slabs Construction Methods: Composite Columns Composite Connections COMPOSITE CONSTRUCTION Types of Composite Materials ❑ Reinforced Concrete and Masonry ❑ Composite Wood (Plywood) ❑ Reinforced Plastics (Fibre-Reinforced Polymer or Fiberglass) ❑ Ceramic Matrix Composites (Composite Ceramic and Metal Matrices) ❑ Metal Matrix Composites ❑ Advance Composite Materials COMPOSITE CONSTRUCTION Types of Composite Materials Reinforced Concrete Reinforced concrete combines traditional cement concrete with steel reinforcement (bars) to take advantage of concrete's compressive strength and steel's tensile strength simultaneously. COMPOSITE CONSTRUCTION Types of Composite Materials Reinforced Concrete Reinforcing schemes are designed to resist tensile stresses in specific areas of concrete that could lead to undesirable cracking or structural failure. COMPOSITE CONSTRUCTION Types of Composite Materials Masonry Masonry refers to bricks or stones bonded together with cement to form walls or buildings. Common materials used in masonry construction include brick, marble, granite, limestone, cast stone, concrete block, glass block, and adobe. COMPOSITE CONSTRUCTION Types of Composite Materials Masonry It is generally considered a highly durable form of construction. COMPOSITE CONSTRUCTION Types of Composite Materials Composite Wood Composite wood refers to a range of wood products made by binding or fixing strands, particles, fibers, veneers, or boards of wood together using adhesives or other methods to form a composite material. COMPOSITE CONSTRUCTION Types of Composite Materials Reinforced Plastics Fibre-reinforced plastic (FRP), also known as fiber-reinforced polymer, is a composite material made of a polymer matrix reinforced with fibers. COMPOSITE CONSTRUCTION Types of Composite Materials Reinforced Plastics The fibers are typically glass (in fiberglass), carbon (in carbon fiber-reinforced polymer), aramid, or basalt. In some cases, other fibers such as paper, wood, or asbestos have been used, though these are rare. COMPOSITE CONSTRUCTION Types of Composite Materials Ceramic Matrix Composites Ceramic matrix composites consist of ceramic fibers embedded in a ceramic matrix. Both the matrix and fibers can be made from various ceramic materials, with carbon and carbon fibers also being considered as ceramic materials in this context. COMPOSITE CONSTRUCTION Types of Composite Materials COMPOSITE CONSTRUCTION Types of Composite Materials Metal Matrix Composites A metal matrix composite (MMC) is a composite material consisting of at least two components, one of which must be a metal. The other material can be a different metal, ceramic, or organic compound. COMPOSITE CONSTRUCTION Types of Composite Materials Metal Matrix Composites When the composite contains at least three materials, it is referred to as a hybrid composite. An MMC is complementary to a cermet, which typically combines metal with ceramic. COMPOSITE CONSTRUCTION Composite Beams A composite beam is structurally similar to a T- beam, with the top flange made of concrete in compression and the steel section in tension. Shear connectors transfer forces between the two materials. COMPOSITE CONSTRUCTION Composite Beams The principle of composite action increases the strength and stiffness of the system, allowing for a smaller steel section to be used. T-Beams for DAMS T-Beams for BRIDGES COMPOSITE CONSTRUCTION Composite Beams A structural member made of two or more dissimilar materials joined together to act as a unit is known as a composite structure. An example in civil engineering is the steel-concrete composite beam, where a steel wide flange shape (I or W shape) is attached to a concrete floor slab. COMPOSITE CONSTRUCTION Steel-Wood Composite Beam COMPOSITE CONSTRUCTION Wood-Concrete Composite Beam COMPOSITE CONSTRUCTION Plastic-Concrete Composite Beam COMPOSITE CONSTRUCTION Composite Slab Composite slabs consist of reinforced concrete cast on top of profiled steel decking, which serves as formwork during construction and as external reinforcement once completed. RE-ENTRANT DECKING TRAPEZOIDAL DECKING COMPOSITE CONSTRUCTION Composite Slab The decking can be either re-entrant or trapezoidal. When the trapezoidal decking exceeds 200 mm in depth, it is referred to as deep decking. RE-ENTRANT DECKING Additional reinforcing bars may be placed in the decking troughs, especially in deep decking, or in shallow decking when heavy loads and high fire resistance requirements are involved. TRAPEZOIDAL DECKING COMPOSITE CONSTRUCTION Composite Slab COMPOSITE CONSTRUCTION Composite Columns Composite columns are made by combining structural steel and concrete to take advantage of the beneficial properties of both materials. COMPOSITE CONSTRUCTION Composite Columns The interactive and integral behavior of the concrete and steel elements makes composite columns stiff, ductile, cost-effective, and structurally efficient, making them ideal for use in building and bridge construction. COMPOSITE CONSTRUCTION Composite Columns Composite columns are made up of a steel profile, typically designed to avoid local buckling, with concrete infill cast between the flanges. COMPOSITE CONSTRUCTION Circular Concrete-Filled Tubes Concrete-filled tubes (CFTs) are composite members with a steel tube filled with concrete, enhancing both materials' strengths. COMPOSITE CONSTRUCTION Circular Concrete-Filled Tubes The concrete is confined by the steel, creating triaxial compression that improves its strength and strain capacity. The steel tube delays buckling, and CFTs are easy to construct, offering strong resistance to compression, bending, and shear. They are ideal for bridge piers and building columns. COMPOSITE CONSTRUCTION Concrete-Filled Rectangular Tubes COMPOSITE CONSTRUCTION Concrete-Filled Tubes Composite H sections can be fully or partially encased (web infill only) or used as concrete-filled hollow sections. In the UK, composite columns requiring formwork are considered less cost- effective. COMPOSITE CONSTRUCTION Concrete-Filled Tubes Concrete-filled hollow section columns are more material- efficient than equivalent H sections and do not require formwork. The concrete infill boosts compression resistance, prevents local steel buckling, and improves fire resistance, potentially allowing the column to be unprotected or lightly protected. COMPOSITE CONSTRUCTION Concrete-Filled Tubes Both rectangular and circular hollow sections are viable, with rectangular sections offering the advantage of flat surfaces for beam-to-column connections using Flowdrill or Hollo-bolt. COMPOSITE CONSTRUCTION Composite Connections Shear Connectors Shear connectors are essential for composite construction, providing longitudinal shear resistance to ensure the beam and concrete slab act as a single unit. COMPOSITE CONSTRUCTION Composite Connections Shear Connectors They facilitate interaction between the materials, resist lateral shear forces and displacement, and prevent the concrete slab from displacing upward from the beam. COMPOSITE CONSTRUCTION Composite Connections Shear Connectors COMPOSITE CONSTRUCTION Composite Connections Shear Connectors COMPOSITE CONSTRUCTION Composite Connections Shear Studs Shear studs are steel pins or grommets welded to the top flange of a steel support beam after the metal deck is placed. The welding process attaches the shear stud directly to the beam through the deck. COMPOSITE CONSTRUCTION Composite Connections Shear Studs The primary function of shear studs is to create a structural connection between the poured concrete slab and the steel beam, allowing shear forces to be distributed across the structure. Without shear studs, a slip plane would form between the concrete slab, metal deck, and steel framework, compromising the structure's integrity. COMPOSITE CONSTRUCTION Composite Connections Shear Bolt/Pin A pin can be a simple metal rod inserted into a drilled channel between two moving parts, holding them in place as long as it remains intact. COMPOSITE CONSTRUCTION Composite Connections Shear Bolt/Pin It can also be used through a hub and axle, with the pin's diameter, alloy, and tempering chosen to ensure it shears only when a specific threshold of force or shock is reached. COMPOSITE CONSTRUCTION Composite Connections Oscillating Perfobondstrip The curved design of an oscillating perfobond strip improves force transfer between steel and concrete more effectively than a continuous strip. It has a higher load capacity than headed studs or welded T- sections and is ideal for lightweight or high-strength normal weight concrete. COMPOSITE CONSTRUCTION Composite Connections Oscillating Perfobondstrip However, a key challenge with this connector is the difficulty in welding it to the steel beam. COMPOSITE CONSTRUCTION Composite Connections Continuous Perfobondstrip The continuous perfobond strip is similar to the oscillating version but offers lower resistance across all types and grades of concrete. Due to its lower performance, it is less commonly used, despite being easier to weld. COMPOSITE CONSTRUCTION Composite Connections Welded T-Section/T-Rib Connectors Welded T-Section connectors perform well compared to headed studs and provide the same load resistance as oscillating perfobond strips. Their load capacity increases when lightweight or high-strength concrete is used. COMPOSITE CONSTRUCTION Composite Connections Welded T-Section/T-Rib Connectors Welded T-Section connectors perform well compared to headed studs and provide the same load resistance as oscillating perfobond strips. Their load capacity increases when lightweight or high-strength concrete is used. COMPOSITE CONSTRUCTION Composite Connections Waveform Strips The objective of the curved form is to enhance force transfer between the steel and surrounding concrete compared to straight connectors. CONSTRUCTION SYSTEMS: CABLE STRUCTURE Prepared by: Ar. Noel T. Amor, Jr. Designed for UM-CAFAE Bachelor of Science in Architecture Program CABLE STRUCTURE What is a Cable? Definition (1): A cable is a flexible structural component which offers zero resistance to shear and bending. Generally, cables are subjected to tensile forces. CABLE STRUCTURE Structural Cables A cable structure is often used in engineering structures as a support and to transmit load from one point to another when used to support roofs, bridges, and other structural members. The cable also form the main load carrying element in the structure. CABLE STRUCTURE Loading Mechanism The high tensile strength of steel, combined with the efficiency of simple tension, makes the steel cable the ideal structural element to span large distances. CABLE STRUCTURE Loading Mechanism In order to understand the mechanism by means of which a cable supports a vertical load, one may first consider a cable suspended between two fixed points, located at the same level and carrying a single load at the mid span. CABLE STRUCTURE Cable Sag The triangular shape acquired by the cable is characterized by the SAG, the vertical distance between the supports and the lowest point in the cable. Without the sag, the cable cannot carry the load since the tensile forces in it would be horizontal, and horizontal forces cannot balance the vertical load. CABLE STRUCTURE Cable Sag The undivided pull of the sagging cable on each support may be split two components: ❑ A downward force equal to half the load ❑ A horizontal inward pull or thrust. CABLE STRUCTURE Cable Systems If the cables is subjected to the external load, it will deform in a way depending upon the magnitude and location of the applied external forces. The deformation acquired by the cable is called the funicular shape of the cable. CABLE STRUCTURE CABLE STRUCTURE Funicular shape F CABLE STRUCTURE Geometric Funicular Forms: Funicular shape F F F Any change of loading or support conditions changes the form of the funicular curve. CABLE STRUCTURE Geometric Funicular Forms: Funicular shape F F If two equal loads are set on the cable in symmetrical positions, the cable adapts itself by acquiring a new configuration. CABLE STRUCTURE Geometric Funicular Forms: Funicular shape F F F F F As the number of loads increases, the funicular polygon approaches a geometrical curve – the PARABOLA. CABLE STRUCTURE Geometric Funicular Forms: Funicular shape F F F F F If the equal loads are distributed evenly along the length of the cable, rather than horizontally, the funicular curve differs from a parabola, though it has the same general configuration – it is a CATENARY. CABLE STRUCTURE Classification of Cable Structures Suspension-type Cable Structures Cable-stayed Type Structures CABLE STRUCTURE Classification of Cable Structures ❑ Suspension-type Cable Structures The basic structural component of a suspension-type system includes stiffening girders/trusses, the main suspension cables, main towers, and the anchorages for the cables at each end of the structure. The main load-carrying member is the main cable, which is a tension members, and is made of high-strength steel. CABLE STRUCTURE Classification of Cable Structures ❑ Suspension-type Cable Structures CABLE STRUCTURE Classification of Cable Structures ❑ Forces on Suspension-type Cable Structures CABLE STRUCTURE Classification of Cable Structures ❑ Suspension-type Cable Structures ❑ These are the cables which run freely through the towers transferring loads through the anchorages at each end. ❑ It must have two towers to work effectively. ❑ It can only support straight bridge. CABLE STRUCTURE Classification of Cable Structures ❑ Advantages of Suspension-type Cable Structures ❑ Strong and can span long distances such as across the rivers. ❑ Cost-effective ❑ Can be built up high ❑ Has Flexibility ❑ Simple Construction CABLE STRUCTURE Classification of Cable Structures ❑ Disadvantages of Suspension-type Cable Structures ❑ Soft ground tissues ❑ Too Flexible ❑ Cannot support high traffic CABLE STRUCTURE World’s Longest Suspension-type Bridges Based on Largest.org 10. Nanjing Fourth Yangtze Bridge Location: Jiangsu, China Date Opened: 2012 Length: 1,418 meters (4,652 feet) Water Body Crossed: Yangtze River CABLE STRUCTURE World’s Longest Suspension-type Bridges Based on Largest.org 9. Dongting Lake Bridge Hangrui Location: Hunan, China Date Opened: 2018 Length: 1,480 meters (4,854 feet) Water Body Crossed: Dongting Lake CABLE STRUCTURE World’s Longest Suspension-type Bridges Based on Largest.org 8. Runyang Bridge Location: Jiangsu, China Date Opened: 2005 Length: 1,490 meters (4,888 feet) Water Body Crossed: Yangtze River CABLE STRUCTURE World’s Longest Suspension-type Bridges Based on Largest.org 7. Yi Sun-sin Bridge Location: South Jeolla Province, South Korea Date Opened: 2012 Length: 1,545 meters (5,069 feet) Water Body Crossed: Gwangyang Bay CABLE STRUCTURE World’s Longest Suspension-type Bridges Based on Largest.org 6. Osman Gazi Bridge Location: Kocaeli Province, Turkey Date Opened: 2016 Length: 1,550 meters (5,090 feet) Water Body Crossed: Gulf of İzmit CABLE STRUCTURE World’s Longest Suspension-type Bridges Based on Largest.org 5. Great Belt Bridge Location: Region Zealand, Denmark Date Opened: 1998 Length: 1,624 meters (5,328 feet) Water Body Crossed: Great Belt CABLE STRUCTURE World’s Longest Suspension-type Bridges Based on Largest.org 4. Xihoumen Bridge Location: Zhejiang, China Date Opened: 2009 Length: 1,650 meters (5,410 feet) Water Body Crossed: Hangzhou Bay CABLE STRUCTURE World’s Longest Suspension-type Bridges Based on Largest.org 3. Nansha Bridge (East span) Location: Guangdong, China Date Opened: 2019 Length: 1,688 meters (5,538 feet) Water Body Crossed: Pearl River CABLE STRUCTURE World’s Longest Suspension-type Bridges Based on Largest.org 2. Yangsigang Yangtze River Bridge Location: Hubei, China Date Opened: 2019 Length: 1,700 meters (5,577 feet) Water Body Crossed: Yangtze River CABLE STRUCTURE World’s Longest Suspension-type Bridges Based on Largest.org 1. Akashi Kaikyō Bridge Location: Honshu, Japan Date Opened: 1998 Length: 1,991 meters (6,532 feet) Water Body Crossed: Akashi Strait CABLE STRUCTURE World’s Longest Suspension-type Bridges 1915 Çanakkale Bridge Location: Northwestern Türkiye Date Opened: 2022 Length: 2,023 meters (6,637 feet) Tower Height: 318 meters Water Body Crossed: Dardanelles Strait CABLE STRUCTURE Classification of Cable Structures ❑ Cable-stayed Type Structures The cable-stayed type is a structural system with continuous girder supported by inclined stayed-cables from the towers. It is a structure with several points in each span between the towers supported upward in a slanting direction with cables, and consists of main towers, cables, and girders. CABLE STRUCTURE Classification of Cable Structures ❑ Cable-stayed Type Structures CABLE STRUCTURE Classification of Cable Structures ❑ Forces on Suspension-type Cable Structures CABLE STRUCTURE Classification of Cable Structures ❑ Cable-stayed Type Structures ❑ These are the cables which runs directly from roadway to the single towers on which the load acts. ❑ It can only have single tower to work efficiently. ❑ It can support curved bridge. CABLE STRUCTURE Classification of Cable Structures Types of Cable-stayed Structures: Based on the arrangement of cables ❑ Radial: cables connect evenly throughout the deck, but all converge on the top of the pier. ❑ Harp: cables are parallel, and evenly spaced along the deck and the pier. CABLE STRUCTURE Classification of Cable Structures Types of Cable-stayed Structures: Based on the arrangement of cables ❑ Fan: a combination of radial and harp types. ❑ Star-shaped: cables are connected to two opposite points on the pier. CABLE STRUCTURE Classification of Cable Structures Types of Cable-stayed Structures: Based on the shape of the pylon CABLE STRUCTURE Classification of Cable Structures ❑ Advantages of Cable-stayed Type Structures ❑ Good for medium span structure. ❑ Greater stiffness than suspension bridge. ❑ Can be constructed by cantilevering out from the tower. ❑ Horizontal forces are balanced so large ground anchorage are not required. CABLE STRUCTURE Classification of Cable Structures ❑ Advantages of Cable-stayed Type Structures ❑ Cable-stayed bridge takes less time to complete that suspension type cable structure. ❑ The cable-stayed bridge supports itself. CABLE STRUCTURE Classification of Cable Structures ❑ Disadvantages of Cable-stayed Type Structures ❑ Cable-stayed bridge has a maximum length to consider. ❑ The design option can become unstable in specific environment. ❑ It can be challenging to inspect or repair ❑ It is a design that can sometimes be susceptible to rust and corrosion. CABLE STRUCTURE Classification of Cable Structures ❑ Construction of Cable-stayed Type Structures CABLE STRUCTURE Classification of Cable Structures ❑ Construction of Cable-stayed Type Structures CABLE STRUCTURE Classification of Cable Structures ❑ Construction of Cable-stayed Type Structures CABLE STRUCTURE Classification of Cable Structures ❑ Construction of Cable-stayed Type Structures CABLE STRUCTURE Classification of Cable Structures ❑ Construction of Cable-stayed Type Structures CABLE STRUCTURE World’s Longest Cable-stayed Bridge Russky Bridge Location: Vladivostok, Primorsky Krai, Russia Date Opened: 2012 Main Span: 1104m (3,622feet) Length: 3100m (10,200feet) Tower Height: 320.9m (1,052.8feet) Water Body Crossed: Eastern Bosphorus strait CABLE STRUCTURE Comparison of Suspension-type Cable and Cable-stayed type Structures Suspenstion-type Cable-stayed Type ❑ Normally limited to two ❑ It can be built with any (2) towers. number of tower. CABLE STRUCTURE Comparison of Suspension-type Cable and Cable-stayed type Structures Suspenstion-type Cable-stayed Type ❑ Suspension bridge ❑ Cable-stayed bridges requires more cable. requires less cable. CABLE STRUCTURE Comparison of Suspension-type Cable and Cable-stayed type Structures Suspenstion-type Cable-stayed Type ❑ Construction time is ❑ Construction time is longer for suspension- less for cable-stayed type structure. structure. CABLE STRUCTURE Comparison of Suspension-type Cable and Cable-stayed type Structures Suspenstion-type Cable-stayed Type ❑ Possess less stiffness ❑ Possess higher and displays larger stiffness and displays deflections. smaller deflections. CABLE STRUCTURE Cable Materials ❑ A cable may be composed of one or more structural ropes, structural strands, locked coil strands or parallel wire strands. ❑ A strand is an assembly of wires formed helically around center wire in a more symmetrical layers. CABLE STRUCTURE Cable Materials ❑ A strand can be used either as an individual load-carrying member, where radius or curvature is not a major requirement, or as a component in the manufacture of structural rope. CABLE STRUCTURE Cable Materials ❑ A rope is composed of a plurality of strand helically laid around the core. In contrast to the strand, a rope provides increased curvature capability and is used where curvature of the cable becomes an important consideration. CABLE STRUCTURE Types of Cable Materials CABLE STRUCTURE Cable Materials ❑ Cables are made of high-strength steel, usually encased in a plastic or steel covering that is filled with a grout, a fine- grained form of concrete, for protection against corrosion. CABLE STRUCTURE Types of Cable Materials CONSTRUCTION SYSTEMS: TENSILE STRUCTURE Prepared by: Ar. Noel T. Amor, Jr. Designed for UM-CAFAE Bachelor of Science in Architecture Program TENSILE STRUCTURE What is a Tensile Structure? Definition (1): A tensile structure is a construction of elements carrying only tension and no compression or bending. The term tensile should not be confused with tensegrity, which is a structural form with both tension and compression elements. Tensile structures are the most common type of thin-shell structures. TENSILE STRUCTURE Tensile Membrane Structure A tensile membrane structure is most often used as a roof, as they can economically and attractively span large distances. TENSILE STRUCTURE What are the advantages of Tensile Structures? 1 2 3 4 5 2 FLEXIBLE OUTSTANDING EXCELLENT LIGHTWEIGHT LOW COST DESIGN TRANSLUCENCY DURABILITY NATURE MAINTENANCE BENEFITS AESTHETICS TENSILE STRUCTURE What are the advantages of Tensile Structures? Tensile membrane structures provide virtually 1 unlimited designs of distinctive elegant forms that can be realized because of the unique FLEXIBLE flexible characteristics of membrane resulting in DESIGN AESTHETICS an iconic and unique structure or feature for any building owner, city or even region. TENSILE STRUCTURE What are the advantages of Tensile Structures? In daylight, fabric membrane translucency offers soft 2 diffused naturally lit spaces reducing the interior lighting costs while at night, artificial lighting creates OUTSTANDING TRANSLUCENCY an ambient exterior luminescence. TENSILE STRUCTURE What are the advantages of Tensile Structures? With several different membranes in the market 3 place such as PTFE fiberglass, ETFE film, PVC, and ePTFE, the durability and longevity of tensile EXCELLENT DURABILITY membrane structures have been proven. TENSILE STRUCTURE What are the advantages of Tensile Structures? The lightweight nature of membrane is a cost- 4 effective solution that requires less structural steel to support the roof compared to LIGHTWEIGHT NATURE conventional building materials, enabling long spans of column-free space. TENSILE STRUCTURE What are the advantages of Tensile Structures? Tensile membrane systems are somewhat 5 unique in that they require minimal maintenance when compared to an equivalent sized LOW MAINTENANCE conventional building. TENSILE STRUCTURE What are the advantages of Tensile Structures? Most tensile membrane structures have high sun 6 reflectivity and low absorption of sunlight, thus resulting in less energy used within a building COST BENEFITS and ultimately reducing electrical energy costs. CONSTRUCTION SYSTEMS: MEMBRANE STRUCTURE Prepared by: Ar. Joyce Marie S. Cagampang Designed for UM-CAFAE Bachelor of Science in Architecture Program MEMBRANE STRUCTURE History of Membrane Structures 1950s - new materials, techniques, and proiceees were developed by novel construction forms Long Span Bridge Technology - inspired a new generation of architects and engineers who pursued a geometrical vision One of the streams of this phenomena of lightweight structures is membrane structures. Fred Severud, Frei Otto, and Walter Bird - notable pioneers who have passed their pioneering zeal to establish main stream design companies and so the new becomes the norm Membrane structures - new color on the architects pallete, highly aesthetic forms and are a dominant feature in building landscape even if the overall construction share is small MEMBRANE STRUCTURE Design of Membrane Structures From the honored craft of tent making, the construction industry now utilizes highly contemporary techniques for design and construction Computers - predominates the engineering design and graphic imaging Complex surfaces resolved swiftly using powerful programs and new generation hardware Design skills are refined through the first challenging decades of work in the field MEMBRANE STRUCTURE Design of Membrane Structures Nowadays competent and experienced design teams approach the most complex works in confidence and the proliferation of built structures increases exponentially The opposite side of the equation is a fabrication and construction industry which ahs experienced dramatic development in the specialized processes involved in assembling structures into the finished project work. MEMBRANE STRUCTURE STRUCTURAL MATERIALS The surface is held under a constantly applied prestress force presenting a film thickness division between inside and outside environments. Materials development has rapidly paralleled design technology improvement to make available truly engineered fabrics designed for a specific purpose. High strength durable synthetic materials are marketed for selection by designers in accordance with specific requirements and building regulations. MEMBRANE STRUCTURE History of Fabric Architecture Exploited by nomadic tribes almost from the dawn of civilization, the use of fabric to provide mankind with shelter from the natural elements of sun, rain, wind and snow is an architectural design strategy whose origins are lost in antiquity. The discovery of high-performance polymers, methods for their incorporation into advanced composites and the development of a computerized methodology for the analysis of their nonlinear, time dependent viscoelastic behaviour. These elements have finally come together over the past twenty years to lend credibility to the concept of permanent fabric architecture. MEMBRANE STRUCTURE What are Membrane Structures? These are buildings made from materials under tension. A cable net supporting a fabric or sheet material or could be made entirely from fabric most often used for roofing , relatively new form of construction. Employes a thin, flexible surface material such as coated fabrics, as their main structural and cladding element. The membrane is usually stressed between its support system and its anchorages. MEMBRANE STRUCTURE What are Membrane Structures? Typical membrane structures are tension structures supported by frames, cables or masts and those which are supported by (internal) air pressure - ”air supported structures.” The fanciful shapes and festive colours of membrane structures make them a perfect choice for many recreational facilities. They provide wide, clear span areas without large supporting members. MEMBRANE STRUCTURE What are Membrane Structures? Foundation requirements are comparatively low; simple footings for the mast or masts and solid anchorages for cable connections at perimeter points. As shelters for performance stages, they can provide a proscenium-like setting without the heavy structure required with other materials. MEMBRANE STRUCTURE What are Membrane Structures? Their ability to provide vast clear span space assures clear sight lines for the audience with minimum of supporting posts. These attributes enable a designer to use his imagination to the fullest. The versatility of tensioned membrane structures makes them useful is a wide range of applications; outdoor dining areas, eye-catching entrance gateways, walkway coverings, shelter for building courtyards, atria roofs for commercial and recreational building, even weather protection for transportation terminals. MEMBRANE STRUCTURE What is a Tensioned Membrane Structures? A special structure that obtains its strength from a combination of its geometric shape - “structural form” - and the properties of the material from which it is manufactured. With a ‘tent’ the fabric is simply a covering for a structural frame, only incidentally contributing to the tent’s structural integrity. MEMBRANE STRUCTURE What is a Tensioned Membrane Structures? In a tensioned membrane structure, the fabric provides a structural membrane. The combination of the membrane and steel cable or arch elements achieves stability so that the smooth curvilinear forms remain stable even under high wind load. MEMBRANE STRUCTURE What is a Tensioned Membrane Structures? When the requirements call for large scale exhibition buildings, membrane structures can be an exposition designer’s best resource. They allow a design freedom not possible with other building materials; shapes which cannot be achieved any other way become possible. Tensioned membrane structures are uniquely suited to the needs of expositions and fairs for exciting, attractive pavilions, exhibition halls and entertainment theatres. MEMBRANE STRUCTURE Definition of a Tensioned Membrane Structures? A membrane structure is a flexible surface (skin, fabric) which is only capable of transmitting tensile stress. It relies on double curvature to achieve its stability in prestress and under wind or other external loads. MEMBRANE STRUCTURE Definition of a Tensioned Membrane Structures? Membranes can be sub-divided into two major groups: Non prestressed membranes Prestressed membranes MEMBRANE STRUCTURE Definition of a Tensioned Membrane Structures? Non prestressed membranes such as tents, sails and air (or other medium) filled structures, which are originally slack in the unloaded condition an assume shapes of either single or double curvature when loaded MEMBRANE STRUCTURE Definition of a Tensioned Membrane Structures? Prestressed membranes such as tension membranes or air-supported structures. Tension membrane structures assume double negative (anticlastic) curvature. Air supported structures assume a double positive (synclastic) curvature. MEMBRANE STRUCTURE Definition of a Tensioned Membrane Structures? Air-supported structures Tension Membrane Structures MEMBRANE STRUCTURE Styles and Shapes of a Tensioned Membrane Structures? Conical Tension Structure Highly effective for covering large areas, a conical tension structure is easily identified by its tent-like shape. Conical designs can feature either single or multiple masts. The masts can go to the ground or can utilize a ‘flying’ mast where cables are used in tension, supporting the mast in the air to allow for an unobstructed space below. Cones are especially effective in areas that need to comply with high rain or snow load regulations. MEMBRANE STRUCTURE Styles and Shapes of a Tensioned Membrane Structures? Hypar or Anticlastic Structure As one of the most common of all tensioned membrane structures due to its aesthetically pleasing look, hypar (hyperbolic paraboloid) shapes are notable for their excellence with shape retention and water runoff. Rely on two opposing curvatures, also known as anticlastic, for their stability, and often resemble the shape of a saddle featuring two high points and two low points, This type of structure is ideal for shade over seating areas or high-traffic walkways. MEMBRANE STRUCTURE Styles and Shapes of a Tensioned Membrane Structures? Parallel Arch or Barrel Vault Structure These symmetrical curved parallel arch designs form an incredibly functional tensioned membrane canopy that can span long distances such as a sports arena or smaller areas such as an entryway. Also known as a barrel vault design, these parallel arch structures come with a wide variety of support systems from traditional arch designs to frame supported or cantilever options. Cost-effective way to incorporate tensile membrane on a project due to the repetitive nature of the design and efficiencies of materials. MEMBRANE STRUCTURE Styles and Shapes of a Tensioned Membrane Structures? Cable Net & Membrane Structure For long-span tensile membrane roofing applications typically found in stadiums or large spaces, 3D cable net or cable grid structures are an efficient solution for lightweight tensile architecture. Using pre-tensioned structural cables where the cables are carrying the primary load of a structure, these types of structures are an effective way to help support and reinforce the PTFE or PVC membrane all while achieving a dramatic and uniquely signature design. MEMBRANE STRUCTURE MATERIALS Several membrane materials are available for permanent structures; coated, woven synthetic fabrics are by far the most widely used. Due to their fabrics from natural fibers hlow durability (2-3 years), ave been almost completely replaced by the more durable and dimensionally stable synthetic or mineral fibers. Preferred fibers for woven fabrics are polyester or glass fiber. Coatings applied to fabric are PVC, Teflon or Silicon is applied to glass fiber fabric. Each class of material has its particular attributes in terms of durability, thermal and optical performance and cost. MEMBRANE STRUCTURE MATERIALS Properties of the Materials ⚬ High Inherent Strength ⚬ Resistance to Environmental Pollution ⚬ Service Life ⚬ Fire Safety ⚬ Thermal Properties of Membranes ⚬ Acoustics ⚬ Lighting ⚬ Color Fastness ⚬ Special Shading Materials MEMBRANE STRUCTURE MATERIALS Properties of the Materials ⚬ High Inherent Strength ￭ Tensile strength is as high as the strength of high-tensile steel ￭ The membrane material is 5 to 6 times lighter ⚬ Resistance to Environmental Pollution ￭ Modern Fabrics have natural dirt-shedding capabilities or are specially treated to achieve a high level of cleanability ⚬ Service Life ￭ Good quality PVC-coated fabric has minimum service life of 10-15 years ￭ Teflon-coated fiberglass has an anticipated minimum life of 25 years MEMBRANE STRUCTURE MATERIALS Properties of the Materials ⚬ Fire Safety ￭ PVC-coted polyester and Teflon-coated fiberglass are fire-safe and meet the requirements ⚬ Thermal Properties of Membranes ￭ Uninsulated Membrane Structures energy efficient in warmer climates but due to their lower thermal mass are relatively ineffective in cold climates ￭ Thermal insulation may be increased in which secondary liners can be added in the case of tension membrane and air- supported structures MEMBRANE STRUCTURE MATERIALS Properties of the Materials ⚬ Thermal Properties of Membranes ￭ Higher Thermal Insulation can be achieved by the use of multi- layered membranes Stratification and venting can be used to advantage ￭ Understanding the properties of individual materials, the effect of form and shape are important to the fabric structure design MEMBRANE STRUCTURE MATERIALS Properties of the Materials ⚬ Acoustics ￭ Air-supported structures address the effect of reverberation time created by the concave surfaces acoustical treatment such as liners or suspended panels with Noise Reduction Coefficients as low as 0.61 is provided by the industry ⚬ Lighting ￭ High degree of translucency one of the attractions of choosing a membrane Light penetrating the membrane provides a unique natural environment MEMBRANE STRUCTURE MATERIALS Properties of the Materials ⚬ Lighting The light quality which will be influenced by the fabric selection is color The light will be balanced, shadowless, and diffuse ￭ At night, the fabric surface provides the opportunity to obtain diffuse radiant lighting effects internally while at the same time a gentle glow penetrates the membrane creating a landmark MEMBRANE STRUCTURE MATERIALS Properties of the Materials ⚬ Color Fastness ￭ Materials are available in a range of color fast pigmentations ￭ However, consideration should be given to the effect on transmitted light and additional heat load into the space below when darker color fabrics are used ⚬ Special Shading Materials ￭ Allow controlled transmission of sun, dew, rain, and protection from frost and hail. ￭ With recent concerns of skin cancer, it is important to be able to predict shade patterns at different times of the day throughout the year. This includes the effects of overlapping panels with curved edges as illustrated below. MEMBRANE STRUCTURE DESIGN CONSIDERATIONS Shape Determination and Cutting Patterns Structural Analysis Structural analysis of membrane structures An accurate scale model may be constructed and involves non-linear static as well as dynamic cutting patterns obtained from it. Alternatively, analysis. computer programs are available to undertake the Without these computer programs it would not patterning of certain materials. be possible to achieve the degree of precision The complexity in the overall design process from required for the design and fabrication of a concept to cutting pattern has led to the fabric structure. The use of models to help development and fabrication of several standard establish initial shapes is still a useful tool. types and shapes for membrane structures. MEMBRANE STRUCTURE COSTS The cost of membrane structures vary dependent upon materials selection, scale of project, complexity and degree of symmetry and construction requirements. To obtain the most cost effective solution it is essential that architectural, structural and mechanical disciplines co-ordinate their design in consultation with specialist fabricators and materials suppliers from the outset. MEMBRANE STRUCTURE ENVIRONMENTAL ISSUES The environmental ’footprint’ of membrane structures is intrinsically low, because in practical terms the self-weight of the membrane is negligible. Hence, the ratio of applied load to self-weight, an inherent measure of the efficiency of material usage, is many times larger than for conventional buildings. By far the majority of membrane structures are fabricated from PVC coated polyester. Despite well publicized claims to the contrary, the CSIRO concluded in a detailed study that in an environmental context, PVC performs as well or better than alternative materials. MEMBRANE STRUCTURE ENVIRONMENTAL ISSUES If one defines sustainable as ”meeting the needs of the present, while ensuring that future generations have the same opportunities”; then PVC is a sustainable product. It is intrinsically recyclable, energy and resource -efficient to manufacture, and being derived from the most basic of basic of hydrocarbons and salt, is a low consumer of nonrenewable resources. MEMBRANE STRUCTURE ENVIRONMENTAL ISSUES Given its expected life of fifteen and twenty- five years, proven by field usage, PVC coated polyester scoreshighly in a life cycle analysis. It is safe to handle, fabricate, and in a building context, has too little mass available to contribute to the fuel load of a fi re. It has excellent UV and heat absorption characteristics. MEMBRANE STRUCTURE SPECIAL CONSTRUCTION FEATURES ❑ Membranes can span ❑ The membrane must ❑ Roof structures are ❑ Stability can be fully ❑ It is important for all large distances be kept tensioned built with spans warranted even under membrane structures without supporting biaxially to obtain exceeding 150m. extreme wind loads. that point loading be structures used in stability and a long ❑ They can be designed ❑ Structures built on avoided. conventional buildings, service life. Certain to bear the same this principle have ❑ Surface slopes must yet these membrane classes of materials loads as their withstood cyclones be steep enough to structures must have higher creep conventional with wind velocities of eliminate ponding always be tensioned properties than others counterparts. 200km/hour. under heavy rain or not in one direction and in these cases snow buildup. but in two to achieve provision for re- their essential stability. tensioning at a later ❑ Flat planar surfaces date may be required. should be avoided.  EXAMPLES MEMBRANE STRUCTURE "The Harbour" of the Swiss National Exhibition  EXAMPLES MEMBRANE STRUCTURE Aarau Bus Terminal  EXAMPLES MEMBRANE STRUCTURE Abuja National Stadium  EXAMPLES MEMBRANE STRUCTURE Abuja Velodrome  EXAMPLES MEMBRANE STRUCTURE Hajj Terminal (Saudi Arabia)  EXAMPLES MEMBRANE STRUCTURE Tokyo Dome (Japan)  EXAMPLES MEMBRANE STRUCTURE Millenium Dome (UK)  EXAMPLES MEMBRANE STRUCTURE  END. Content Contributors: Ar. Noel T. Amor, Jr., Ar. Joyce Marie S. Cagampang, Ar. Ken Benjamin T. Camao, Ar. Raysnil R. Lumpay