Cast-in-Place and Precast Concrete Construction

ARC 180 Building CAST-IN-PLACE Technology 5 – AND PRECAST Alternative Building Construction CONCRETE Systems GROUP 3 LEADER: I N I B A , C AT H L E N E G R A C E...

ARC 180 Building CAST-IN-PLACE Technology 5 – AND PRECAST Alternative Building Construction CONCRETE Systems GROUP 3 LEADER: I N I B A , C AT H L E N E G R A C E MEMBERS: R A B I N A , L E I A N N E J OYC E S O R I A N O , A N G E LO MENDOZA, CAMILLE CERALDE, CHANEL Cast-In-Place Cast-in-place concrete, also known as “site-cast” or “pour-in-place” concrete, is directly poured and cured onsite in the concrete’s finished position. Cast-in-place concrete is ideal for very large concrete components as they would be difficult to transport between a concrete plant and a job site. (Cast-in-place is a method of building concrete structures using removable formwork. Cast-in-place concrete was used primarily for below- grade basement walls after the patent of Portland cement, a product and company founded by Thomas Edison.) Cast-In-Place Precast Concrete Precast concrete is a durable and sustainable material that can withstand harsh weather conditions and is fully recyclable at the end of its life cycle. From faster construction timelines and lower labor costs to greater design flexibility and customization, it is changing the way we build. Precast concrete is made by pouring concrete into a mold in a factory or plant, instead of directly pouring it at the construction site. The cured concrete product is then transported to the construction site and installed as a finished material. However, there are several different types of precast concrete. Precast Concrete Types of Cast-in-Place Concrete Roof and Floor Systems  Pan Joist  Flat Plate  Flat Slab  Waffle Slab Types of Cast-In-Place  Pan Joist One-way structural system that uses a ribbed slab formed with elongated pans. Types of Cast-In-Place  Flat Plate A two-way reinforced structural system that uses a slab of uniform thickness. Types of Cast-In-Place  Flat Slab A two-way reinforced structural system that uses a slab of uniform thickness with additional depth at columns. Types of Cast-In-Place  Waffle Slab A two-way structural system that uses square domes with concrete place on top. Casting a Concrete Wall Concrete walls on the ground level are cast on top of concrete strip footings. The concrete strip footings are poured in the same manner as a slab-on-grade. Concrete strip footings can also contain a key (groove) that serves as a mechanical connection between the strip footing and the concrete wall. Casting a Concrete Column Concrete columns are cast much like concrete walls, but the footing they are placed on isn’t a strip footing. Concrete columns on the ground level are placed on top of isolated column footings, pile cap footings, or caissons. One-Way Floor and Roof Framing Systems  One-Way Solid Slab A one-way solid slab spans across columns and walls in what looks like a single sheet of concrete. It is called a one-way solid slab because all the beams in the slab run in one direction. The slab formwork can be erected once the walls and columns are created. A one-way solid slab formwork includes the beams. This means that the slab and the beams are all poured simultaneously for each floor. One-Way Floor and Roof Framing Systems  One-Way Concrete Joist Slab (Ribbed Slab) As a one-way solid slab span increases a thicker, and thicker slab is required. Eventually, it gets to the point where the slab becomes so heavy that the slab can’t support its weight. That is why the one-way concrete joist slab, also called a ribbed slab, was created. One-Way Floor and Roof Framing Systems  Wide-Module Concrete Joist (Skip-joist) System When a slab has a thickness greater than 4.5 inches, it means that the slab can span distance far longer than a standard one- way solid slab. That is why the wide- module concrete joist system was created. It is essentially the same as a one-way concrete joist-slab, but every other joist isn’t included, which is why it is also called the skip-joist system. Two-Way Floor and Roof Framing Systems  Two-Way Flat Slab & Two-Way Flat Plate When concrete columns can be arranged in square proportions, the two-way slabs are more cost-effective than one-way concrete slabs. Their most common application is in industrial buildings that have heavy building loads. In use cases with heavy building loads, both the two-way flat slab and the two-way flat plate are created by running a series of beams in both directions. Two-Way Floor and Roof Framing Systems  Two-Way Waffle Slab A waffle slab, also known as a two- way concrete slab system, resembles the one-way concrete joist system. The critical distinction is that joists run in two directions perpendicular to each other. The two-way waffle slab allows for considerably longer spans than the two-way flat slab because it eliminates almost all non-working concrete, meaning that all concrete is used for structural purposes. Types of Precast Concrete  Precast Concrete Walls  Precast Concrete Beams and Columns  Precast Concrete Slabs and Planks  Precast Concrete Stairs  Precast Concrete Retaining Walls Types of Precast Concrete  Precast Concrete Walls These are large concrete panels that can be used to create exterior or interior walls. They are typically manufactured in large, rectangular panels that can be connected and installed quickly at the construction site. Types of Precast Concrete  Precast Concrete Beams and Columns They are designed to provide structural support to buildings or bridges, and are manufactured in different shapes and sizes depending on specific load requirements. Types of Precast Concrete  Precast Concrete Slabs and Planks These are flat panels that can be used as floors or roofs in buildings. They are typically manufactured in long, thin sections that can be easily transported and installed at the construction site. Types of Precast Concrete  Precast Concrete Stairs These are pre-manufactured elements that can be utilized to construct staircases in buildings. They come with pre- installed treads and risers and can be customized to meet specific building design requirements. Types of Precast Concrete  Precast Concrete Retaining Walls These are elements that are used to retain soil or other materials. They are typically manufactured with interlocking edges that can be connected to create a continuous wall, and can be designed to meet specific load requirements. It is important to note that the strength of concrete is affected by several factors, including the quality of the concrete mix, the curing conditions, and the age of the concrete. Therefore, multiple samples often undergo a compressive test of concrete to ensure the quality. Process of Cast-In-Place (in the Philippines) Cast-in-place concrete is poured on-site and will generally take up to 28 days to be ready, or cured. After this period of time, the concrete will have its full strength and be ready for installation. Because of this, cast-in-place does have a relatively longer installation time compared to precast concrete. Cast-in-place can be used to create multiple aspects of your structure including the foundation, walls, and beams. The process of creating these slabs and elements is very labor-intensive and time-consuming. Workers have to pour the ready-mix concrete either by truck, concrete conveyor, or even manually from a wheelbarrow. Process of Cast-In-Place (in the Philippines) 1. Site Preparation and Surveying 2. Formwork Installation 3. Reinforcement Placement 4. Concrete Mix Design 5. Concrete Pouring 6. Curing 7. Formwork Removal 8. Finishing 9. Post-Pour Inspections 10. Project Continuation Process of Precast Concrete  Precast concrete is poured into a reusable mould or ‘form’, cured in a controlled environment, then lifted into place.  Precast concrete can be poured on site and then lifted, or poured off site and transported to site before lifting.  Precast concrete can be used for floors, walls, or roofs of any building. As with other concrete products, it has high embodied energy and can be used to provide thermal mass in passive design.  Precast concrete is durable and requires minimal maintenance.  Precasting can provide a fast constructing process. However, careful design and planning is needed to ensure the openings and other details meet the design needs. Process of Precast Concrete  Design and engineering  Rebar cage assembly and form preparation  Mixing and placement  Curing and monitoring  Demoulding and quality assurance  Transportation and installation Importance of Cast-In-Place in Construction Cast-in-place concrete structures can withstand harsher weather and greater loads because they are subjected to these from the beginning. This strategy creates a structure with high compressive strength, and when steel reinforcement is added, this also includes tensile strength. A few benefits of cast-in-place concrete are that it is fairly disaster-resistant, has a high degree of insulation, is generally sound and insect-proof and is easy to modify or customize. Importance of Precast Concrete in Construction Precast concrete allows for faster on-site construction, reducing overall construction time and increasing project efficiency. It is a durable material that can withstand harsh weather and heavy loads, while also being resistant to fire, rot, and insects, making it a long-lasting choice. Time-Saving. This is one of the most popular advantages of precast concrete. It's easy to prepare your site simultaneously while the precast concrete materials are being manufactured in the factory. So, by the time your elements are ready, so is your site ready for them to be assembled. Difference between Cast-In-Place and Precast Concrete Difference between Cast-In-Place and Precast Concrete Cast-in-place concrete is a technique used in the construction of buildings where walls and slabs of the buildings are cast at the site in formwork. Cast-in-place concrete, also known as “site- cast” or “poured-in-place” concrete, is poured and cured on site in the concrete's finished position. This is ideal for a number of uses. For cases where it would be difficult to transport large concrete parts, it makes more sense to have them cast in the same place they would be used. That’s why it’s commonly used for smaller projects, which can cost more. Difference between Cast-In-Place and Precast Concrete Precast concrete is sometimes referred to as “prefabricated” or premade concrete. What that essentially means is that it is created offsite, at a different location, and then brought on-site when it is needed. Precast concrete products are created by pouring a mixture of cement into a premade mold that can contain wire mesh, rebar, or even steel cables. The mold, now filled with cement, is then cured in a controlled environment so that the material can set and ensure greater material quality. Now, since this all takes place offsite, that means the product is ready for use right away, a necessity in today’s time-restrained construction industry. This makes precast very versatile and it is used in the following:  Culverts  Retaining walls  Pillars and columns; and  Building construction, to name a few. Precast vs. Cast-In-Place in the Philippines Cast-in-place has been used in the country since modern building techniques were adapted and developed. However, with the development of precast, which is not a new technique by far, we now have an alternative building option that can cut down on manpower, time, and of course, cost, in the long run. Additionally precast is more cost-effective for anyone looking for a fast Return on Investment (ROI) because:  Labor management is greatly reduced when working with precast structures. Often, the cast-in- place method requires multiple trades and inspectors to be managed throughout the construction process.  Cost variations between cast-in-place and precast occur in the cost of formwork, reinforcement, cost of workmanship, and concrete in slabs and columns. Both instances require more in each aspect, hence being more expensive during construction. Precast vs. Cast-In-Place in the Philippines In regions with frequent rain such as the Philippines, precast structures are recommended due to their high compressive strength which gives them the ability to withstand storms, strong winds, and even storm surges. Precast structures are also seismic-resistant so less damage is incurred during these natural disasters that are quite common in an archipelago. Essentially, the cost is justified from construction to its long-term benefits. THANK YOU!