Foundation Engineering PDF

FOUNDATION ENGINEERING FUTURE ENGINEERS Gura, John Stephen G. Manabe, Ian Clark P. | Estacio, Johann Sebastian A. J^2 + I WHAT IS FOUNDATION ENGINEERING? ▪ is a branch of geotechnical engineering which applies soil mecha...

FOUNDATION ENGINEERING FUTURE ENGINEERS Gura, John Stephen G. Manabe, Ian Clark P. | Estacio, Johann Sebastian A. J^2 + I WHAT IS FOUNDATION ENGINEERING? ▪ is a branch of geotechnical engineering which applies soil mechanics, structural engineering, and project serviceability requirements for design and construction of foundations for onshore, offshore, and in-land structures. ▪ Foundation engineering can be realized as an “artistic” approach rather than a routine procedure because well-designed and constructed foundations continue to perform efficiently during the lifetime of a project. ▪ In this report we will discuss the foundation engineering ▪ Future CE Manabe will discuss the types of soil ▪ Future CE Gura Will discuss the key aspects of foundation engineering ▪ Future CE Estacio will discuss the types and usage of rebar TYPES OF SOILS IN FOUNDATION ENGINEERING Soil types are divided into the major classes of coarse-grained, fine- grained, organic soils, and peat, each with subgroups and unique characteristics. The system does not describe moisture or density characteristics of freshly sampled soil. WHAT IS COARSE - GRAINED ▪ Coarse-grained rock, soil, paper, material, etc. is rough, or has pieces in it that are larger than usual: This kind of sugar is coarse-grained, but works well in the recipe. Peridotite is a coarse-grained, igneous rock. Linen is a coarse-grained fabric. WHAT IS FINE GRAINED SOIL ▪ Soil with particle size less than 0.075 mm is called Fine-Grained soil (Silt or Clay) and soil with particle size between 80 mm to 0.075 mm is called Coarse-Grained soil. However, soil with particle size less than 0.002 mm is called Clay, and soil with particle size in between 0.075mm to 0.002 mm is WHAT IS ORGANIC – GRAINED AND PEAT ▪ Peat soil, known as one of the most problematic soils in the fields of civil and environmental engineering, is formed by the accumulation and decomposition of organic materials (derived from plant remains) under the waterlogged environment where  CLASSIFICATION OF SOIL SAMPLES TYPE A SOIL TYPE B SOIL ▪ Type A Soils are cohesive ▪ Type B soil has medium soils with an unconfined unconfined compressive strength; compressive strength between 0.5 and 1.5 of 1.5 tons per square tons per square foot. foot (tsf) (144 kPa) or Examples of Type B soil greater. Examples of include angular gravel, Type A cohesive soils are silt, silt loam, and soils often: clay, silty clay, that are fissured or near sandy clay, clay loam and, sources of vibration, but in some cases, silty clay could otherwise be Type A. loam and sandy clay loam Type C soil is the least stable type of soil.  TYPE C SOIL ▪ Soils are cohesive soils with an unconfined compressive strength of 0.5 tsf (48 kPa) or less. Other Type C soils include granular soils such as gravel, sand and loamy sand, submerged soil, soil from which water is freely seeping, and submerged rock that is not stable. EQUIPMENT FOR SOIL ANALYSIS - Auger - Triaxial Test Apparatus - pH metter - Consodilation Apparatus and soil testing - Soil grinder - Direct shear 11 - Liquid limit devices - Compression Proving Ring and more AUGER ▪ Auger drilling for foundation engineering. Auger drilling is a method for installing auger piles and is usually done for drilling in minor depths through loose rock. Installing the piles via auger drilling helps in balancing the load of a construction in deeper soil layers. TRIAXIAL TEST APPARATUS ▪ Triaxial test apparatus enables engineers to assess material strength, deformation, and stability, supporting critical infrastructure design and safety analysis. Below is a detailed overview of the types of triaxial test apparatus, its working mechanisms, and applications in civil engineering projects PH METER ▪ A pH meter is an instrument used to measure hydrogen ion activity in solutions - in other words, this instrument measures acidity/alkalinity of a solution. The degree of hydrogen ion activity is ultimately expressed as pH level, which generally ranges from 1 to 14. CONSOLIDATION APPARATUS AND SOIL TESTING ▪ Consolidation test is used to determine the rate and magnitude of soil consolidation when the soil is restrained laterally and loaded axially. The Consolidation test is also referred to as Standard Oedometer test or One- dimensional compression test SOIL GRINDER ▪ Soil grinders are laboratory tools that are effectively used to reduce agglomerations of caked soil to individual grains with repeatable results. The use of soil grinders saves time and money as compared with the use of mortar and pestle methods. DIRECT SHEAR 11 ▪ The direct shear test includes the testing of a square prism of soil that is laterally restrained and sheared along a mechanically involved horizontal plane while being subjected to pressure applied along a plane normal to the shearing plane. LIQUID LIMIT DEVICE ▪ The liquid limit device is used to determine the moisture content at which clay soils pass from a plastic to a liquid state. This model is hand operated with left side crank and hard rubber base. COMPRESSION PROVING RING ▪ The proving ring is a device used to measure force. It consists of an elastic ring of known diameter with a measuring device located in the center of the ring. Proving rings come in a variety of sizes TYPES OF SOIL BEHAVIOR Cohesive soils A cohesive soil has an attraction between particles of the same type, origin, and nature. Therefore, cohesive soils are a type of soil that stick to each other. Cohesive soils are the silts and clays, or fine-grained soils. Soft soils Soft soil refers to soft plastic and fluid plastic clay with large natural water content, high compressibility, low bearing capacity and low shear strength. KEY ASPECTS OF FOUNDATION ENGINEERING SOIL INVESTIGATION Soil Investigation or geotechnical investigation is a procedure that determines the stratigraphy (study of rocks) and relevant physical properties of the soil underlying the site. This is done to ensure that this substructure, which is eventually going to hold up homes, is safe and enduring.  SHALLOW FOUNDATIONS Shallow foundations are, usually, embedded from one to two meters beneath the final finish elevation. Spread footings are one of the most common types of shallow foundations. Spread footings consist of strips or pads of concrete (or other materials) which extend below the frost line and transfer the building loads to the underlying soil or rock. Another type of shallow footing is the slab-on-grade footing where the building loads are transferred to the soil through a concrete slab placed at the surface. Shallow foundations mainly work by distributing loads on a greater area where the contact pressure is limited within acceptable limits. EXAMPLES OF SHALLOW FOUNDATION ▪ Strip Footing ▪ Mat or Raft foundation ▪ Spread footing ▪ Slab on grade foundation ▪ Column footings ▪ Cantilever or Strap footing STRIP FOOTING ▪ A strip footing is used to distribute the weight of a load-bearing wall over a floor area and can be made of plain or reinforced concrete. The width of the strip foundation is determined by the permissible ground pressure and the load of the building. Strip foundations are the most commonly used type of footing. MAT OR RAFT FOUNDATION ▪ A raft foundation, also called a mat foundation, is essentially a continuous slab resting on the soil that extends over the entire footprint of the building, thereby supporting the building and transferring its weight to the ground SPREAD FOOTING ▪ Spread footings, also known as isolated footings, are a type of foundation commonly used to support individual columns or isolated loads. They work by distributing the structural loads over a larger area of soil, reducing the pressure on the underlying ground and preventing settlement or tilting. SLAB ON GRADE FOUNDATION ▪ The "slab on grade" is concrete poured over a layer of an approved vapor barrier material that is usually placed on a base of gravel to allow better drainage. It is placed directly on the ground (grade) level. COLUMN FOOTINGS ▪ A column footing is a square or rectangular base that supports a column, distributing the load to prevent settlement and ensure stability. CANTILEVER OR STRAP FOOTING ▪ The combined action of the eccentric footing (strap footing), strap beam, and inner column foundation, or any structure constructed to rest the strap beam is the combined footing. Due to the cantilever nation of the strap beam, this type of footings is named cantilever footing.  DEEP DOUNDATION A deep footing is an engineered structure used to transfer load from a structure to stronger deeper soil layers or bedrock. Different types of deep foundations include driven piles, drilled piles, drilled shafts, caissons, piers, earth stabilized columns, and helical piles. Historically, timber piles were amongst the first used. Today most piles are constructed with steel , reinforced concrete, or pre-tensioned concrete. LOAD BEARING CAPACITY refers to the maximum amount of weight or load that a structure, foundation, or material can support without experiencing excessive deformation, stress, or failure. Determining the load-bearing capacity is crucial to ensure the safety and integrity of a structure or component. Examples: Mansory walls Reinforced concrete walls And steel frame structures SETTLEMENT AND STABILITY Foundation settlement refers to the gradual sinking or movement of a building's foundation over time. While often imperceptible to the naked eye, it can have profound consequences for the structural integrity and long-term stability of a construction project. Examples: when an excessive load is applied to the surface or the ground is excavated to make tunnels. Soil settlement can have catastrophic consequences, such as the collapse FOUNDATION DESIGN AND CONSIDERATIONS Several design considerations must be taken into account when designing a foundation. Critical considerations include foundation type, depth, soil bearing capacity, soil type, frost protection, foundation materials, and load transfer. FOUNDATION CONSTRUCTION TECHNIQUE These actions contain the basics of construction techniques, namely, digging the ground or rock, compacting the ground to make a foundation, transporting materials, processing and assembling various materials to make buildings or structures. SEISMIC CONSIDERATIONS In earthquake-prone areas, foundation design must account for dynamic loading and soil liquefaction, which could cause foundation failure ENVIRONMENTAL AND SUSTAINABILITY CONCERNS Modern foundation engineering increasingly focuses on sustainability, minimizing environmental impact during construction, and using materials that are energy-efficient and recyclable. PROPER USAGE AND PLACEMENTS OF STEEL REBARS  STEEL REBAR PLACEMENT ▪ A mesh of steel wires or a steel bar, when massed as reinforcing steel or reinforcement steel, is called Steel Rebar. Steel rebar is used in reinforced concrete and masonry structures to strengthen. ▪ Reinforced can withstand high compressive forces, but it breaks under tension, as it has low tensile strength and requires reinforcement. The high tensile strength of Rebar makes it ideal for casting with a concrete structure. It strengthens the building structure by increasing its tensile strength and ability to carry tensile loads. A steel-reinforced concrete structure can withstand high tension and doesn’t break easily, as observed in large building structures.  CONCRETE ENCASEMENT ▪ The right amount of concrete encasement is essential for the sustainability of the structure concrete cover saves steel rebar from exposure to deicing materials that lead to corrosion. Corrosion of steel rebar increases the diameter of steel due to which concrete outside the steel falls off or loosens from the reinforced steel leading to a weak structure. If less amount of concrete cover leads to corrosion, an excess amount of concrete cover also reduces the structural strength due to the flexural design theory.  POSITIONING OF REBAR ▪ The design of a structure is mostly dependent on rebar positioning. If you lower the top bars or raise the bottom bars even by half-inch more than required in the 6-inch slab, it can reduce the load-carrying capacity of the structure by 20%. ▪ Reinforcing bar supports must be used wherever required. Use supports made of steel wire, precast concrete, or plastic that comes in various heights and support reinforcing bar of specific sizes and positions.  POSITIONING OF REBAR ▪ The design of a structure is mostly dependent on rebar positioning. If you lower the top bars or raise the bottom bars even by half-inch more than required in the 6-inch slab, it can reduce the load-carrying capacity of the structure by 20%. ▪ Reinforcing bar supports must be used wherever required. Use supports made of steel wire, precast concrete, or plastic that comes in various heights and support reinforcing bar of specific sizes and positions. TWO TYPES OF METHODS REBAR PLACEMENT 1.Manual methods 2.Mechanical methods  MANUAL METHOD ▪ The manual method is performed by placing the reinforced steel by hand before placing the concrete on it the reinforcing steel is supported by a chair or small metal to achieve the required height of the steel in the slab. ▪ Stepwise manual placement of steel reinforcement is - ▪ Step 1: Placement of transverse bars with the help of supports or chairs. ▪ Step 2: Putting the longitudinal bars on top ▪ Step 3: Tie the longitudinal bars with the transverse bars at every 1.2m to 1.8 m distance.  MECHANICAL METHOD ▪ The development of mechanical methods for rebar placement has fastened the process where contractors can lay 6000ft or more reinforcement in less than ten days. This method of rebar placement got grouped into two categories, i.e., mesh depressors and bar placers. The purpose behind developing mesh depressors was to place the reinforcement in one lift. Bar Placers group uses bar vibrator machines, tube assembly, and rebar installer equipment for rebar placement.  MECHANICAL METHOD ▪ The development of mechanical methods for rebar placement has fastened the process where contractors can lay 6000ft or more reinforcement in less than ten days. This method of rebar placement got grouped into two categories, i.e., mesh depressors and bar placers. The purpose behind developing mesh depressors was to place the reinforcement in one lift. Bar Placers group uses bar vibrator machines, tube assembly, and rebar installer equipment for rebar placement.  BAR SPACING ▪ The placing drawing specifies where the reinforcement is placed the ironworkers should go through the structural and placing drawings before the placement of reinforcement bars and relate it to the overall structure. ▪ Rebar is commonly spaced at intervals of 18 to 24 inches, center-to-center, both ways in a grid pattern, and fastened together with wire where they meet.  BAR SUPPORTS AND IT'S SPACING ▪ Bar supports hold the reinforcement bars while placing the concrete over it and reach the concrete cover at a certain depth that secures the bars from corrosion. The range of bar supports is from plain concrete blocks to all- plastic chairs and to wire bar supports. These bar supports are not designed or intended for construction equipment like concrete pumps, buggies, or laser screeds. ▪ Bar support spacing is dependent on the size of the reinforcement bar it is supporting. For example, for support of a one-way slab with #5 temperature shrinkage bars, we should use high chairs at 4 feet in the center. Whereas, for 4 bars, place high chairs at 3 feet in the center.  CONCRETE PLACEMENT ▪ Avoid the ill practice of hooking, the placing of reinforcement on the subgrade, and pulling it during concrete placement or settlement in slab construction. The reinforcement bars should not be adjusted when concrete is settled or fixed, and reinforced bars not placed on concrete layers.  BAR TYING ▪ To hold and secure the rebar in place, they should be tied together using wires. Some of the ways of tying are snap tie (for rebar in flat horizontal position), wrap and snap tie (vertical wall reinforcement), saddle tie (column corner bars & stirrups to beam corner bars), and figure-eight tie (for heavy mats). WHY USE REBAR IN CONCRETE FOOTINGS? ▪ Increased strength and durability: Rebar provides tensile strength to the concrete footings, which helps to resist cracking and breakage due to the weight of the structure above and the natural settling of the ground. This additional reinforcement ensures the footings can better support the load and remain stable over time. ▪ Improved load distribution: Rebar helps to distribute the weight of the structure evenly across the footing, reducing the risk of uneven settlement and potential damage to the structure. This uniform load distribution is particularly important in areas with variable soil conditions or where the footing is subject to heavy or concentrated loads. ▪ Crack control: Concrete is strong in compression but weak in tension. As a result, it is susceptible to cracking under tensile stresses, such as those caused by ground movement, temperature fluctuations, or shrinkage during curing. Rebar reinforces the concrete, providing tensile strength and helping to control and minimize the size and frequency of cracks in the footing. ▪ Enhanced structural integrity: Adding rebar in footings connects the footing to the rest of the structure, such as columns, walls, or slabs, creating a cohesive and unified system that works together to support the building. This interconnectedness enhances the overall structural integrity and stability of the building. ▪ Compliance with building codes and standards: Many building codes and standards require the use of rebar for footings to ensure adequate structural performance and safety. Using rebar in your footings will help ensure your construction project meets these requirements, reducing the risk of costly issues, delays, or penalties. TYPES OF REBAR ▪ Steel rebar: The most common type of rebar used in construction, steel rebar provides excellent strength and durability. ▪ Fiberglass rebar: A lightweight, corrosion-resistant alternative to steel rebar, fiberglass rebar is ideal for environments with high moisture or chemical exposure. ▪ Stainless steel rebar: Offering exceptional corrosion resistance, stainless steel rebar is a more expensive option but can be a cost-effective choice in the long run for structures exposed to corrosive elements. ▪ Galvanized rebar: Steel rebar with a protective zinc coating, galvanized rebar resists corrosion better than uncoated steel. ▪ Epoxy-coated rebar: Another corrosion-resistant option, epoxy-coated rebar features a protective epoxy coating that prevents rusting. Footing Type Suggested Rebar Sizes Residential Wall Footings #4, #5 Column Footings #5, #6, #8 Deck Footings #4, #5 Slab Footings #4, #5 Grade Beams #5, #6, #8 Retaining Wall Footings #5, #6, #8 Bridge Pier Footings #8, #9, #10 Industrial Footings #6, #8, #10 ANY KWISTYONS ▪ ANG HINDI MAG CLAP MA BAGSAK