Ching in reading seven talks about masonry arches, masonry lintels, wood beams, wood joists, wood sub-floor/decking, wood plank/beams, steel beams, steel open-web joists, metal decking, and reinforced concrete beam.Masonry arches utilize the compression strength of brick and stone to span openings by transforming
the vertical forces of a supported load into inclined components. Masonry lintel where describe in many different forms of diagrams. wood in general was also described in the way they are used and positioned. Steel overall was explained in its constructional way in use. Metal decking is corrugated to increase its stiffness and spanning capability. The last thing discussed was Reinforce Concrete Beams. Ching explains how they are designed to act together with
longitudinal and web reinforcement in resisting applied forces.
Category: Uncategorized (Page 4 of 12)
According to Ching in his book Masonry arch utilize the compressive strength of brick and stone to span openings by transforming the vertical forces of a supported load into inclined components. We have different of Archs one is the Roman Arch, Gothic Arch and a Jack Arch. Wood joist floors are an essential subsystem of wood light frame construction. Joist span is related to magnitude of applied loads, species and grade of lumber used. Wood subflooring is the structural material that spans across floor joists, serves as a working platform during construction and provide a base for the finish flooring. It includes Panel subfloor, Underlayment and or even combined Subfloor and Underlayment. Steel Beams is more structurally efficient wide flange W shapes have largely superseded the classic I beamS shapes it also can be in a C shape as well. Metal decking is corrugated to increase its stiffness and spanning capability. There are three major types f metal decking Form Decking, Composite Decking and Cellular Decking. Reinforced concrete beams are designed to act together with longitudinal and web reinforcement in resisting applied forces. The top and bottom bars are longitudinal bars serving as tension and the part in the middle is surving as compression.
For this reading, Ching once again goes into materials, but talks about what specific purpose each subcategory of material does, along with some general rules of thumb. For masonry arches and lintels, he explains how each structure is made, what its purpose is, how they differ from each other, and what general spans they come in. As for wooden joists, beams, subflooring, decking and planks, he tells us examples of how they are made, showed us the length of them, what each wooden structure means/represents, and tells us how to properly use each and every structure. Ching also goes back to the topic of steel, giving us a sense of how beams and open-web joists work. Open-web joists are joists that form a sort of “web” seen through sections. These webs help join together beams and other supports. Metal decking come in three forms, composite, form and cellular decking. Composite decking is used to balance tensions with concrete slabs that have a ribbed pattern. Form decking is used for formwork on reinforced concrete slabs. Cellular decking is done by welding a corrugated sheet on to a steel sheet, forming spaces for engineering/electrical work.
In this reading Ching talks about the rules of thumb for masonry arches and lintels; wood beams, joists, decking and planks; steel beams; metal decking; and reinforced concrete beams. Masonry arches and lintels nees to be in a certain shape, curve, and structure to be able to withold the load of the roof or the floor above. Wooden joists need to be at certain span depending on the magnitude of applies loads, its size and spacing, species and grade, and deflection allowed for intended use. Wooden beams need to be carefully examined for the use and there are different types for different uses. Wooden subfloorings are used as a working platform in construction and as a base for the finished flooring. Depending on how it is laid, the outcome will be different. For example, if placed correctly it will lessen floor squeaking and creeping. Wooden decking comes in different styles of connections and span ranges. Wood plank and beams are used as a skeleton frame structure and depending on how it is built it can affect the whole structure. Next are steel beams. Steel beams come in a variety of shapes for a different use. When using steel it is best to use the lighest section that will resist bending. Also there are different ways to connect steel beams such as welding and bolting. Open web steel joists are steel trusses. There are different series that depend on the load and span. Where the open web joist framing is supported also has rules so the stresses are in equilibrium. Metal deckings are corrugated to increase stiffness and spanning and there are three types: form decking, composite decking, and cellular decking. Lastly, reinforced concrete beams need to have good steel reinforcement to support and hold the concrete in place.
Every material can span onto a certain point, they all have limits. Wood for example can only have a span of about 40 feet (depends on the load); that is the max in order to carry the wood onto a truck. Rules of thumb means the general concepts on making something, this can vary depending on the material (wood, steel, concrete) you use. In other words, you have to use your own understanding on how to make such material, rules of thumb is not something that is strictly intended to be accurate or reliable. it’s more like a guide on how to start things. Example (Page 4.04 on Building Construction Illustrated) “Rule of thumb for estimating depth of a concrete beam: span/16′”- Francis Ching. What Ching means is that 16′ feet is the “standard” principle on making the depth of the concrete beam.
In reading these weeks, Ching went deep with many of the basic building materials that we are using today. Some of them are made of wood, masonry, concrete, steel and stone. Because of its qualities, each material has its own advantages when used and some or used instead of others. Concrete is made by mixing different aggregates with enough water and in combination with steel is very useful. Masonry is basically stonework and when stacked on top of each other, it is very useful. Therefore, steel has strength and hardness qualities for making it more preferable with concrete. Wood is good for convenience where the material itself is strong, durable, lightweight and easy to use. Stone is a combination of many materials and it needs to fulfill all these requirements in order to become stone: strength; hardness; durability; work ability; density and appearance. As stated before each building material, certain criteria must be met to select the use when building a structure.
In this section of the book Ching speaks about Masonry arches, lintels, wood joists floors, wood subfloors, wood plank, beam,steel open web joists, and reinforced concrete beams. Masonry arches utilize the compressive strength of brick and stone to span openings by transforming the vertical forces of a supported load into inclined components. A lintel is a structural horizontal block that spans the space or opening between two vertical supports. Wood joists floors are an essential subsystem of wood light-frame construction. The dimension lumber used for joists is easily worked and can be quickly assembled on site with simple tools. Wood subflooring is the structural material that spans across floor joists, serves as a working platform during construction, and provides a base for the finish flooring. Wood plank-and-beam floor systems are typically used with a supporting grid of posts or columns to form a skeleton frame structure. Open-web joists are lightweight, shop-fabricated steel members having a trussed web. Lastly reinforced concrete beams are designed to act together with longitudinal and web reinforcement in resisting applied forces.
Reading #7: Spans Fernandez, Andy
In Ching’s BCI book, he discusses spanning elements and their relationship to their structural importance. A major spanning element is the arch. Arches span spaces using the compressive strengths of brick or stone while depending on the resistance of thrust by the wall. The size of the masonry units dictates the size of the arch. Another spanning tool is the lintel. Lintels span spaces of 4’-6’ respectively. They are made of one of four ways, steel angle supports, Reinforced brick filled with grout spans (8”-12”), concrete lintels with cement grout and precast lintels made of brick or concrete.
Other spanning elements include wood floor joists, decking, sub flooring, wood planks and steel open web joists. Floor joists span from 12”-24” O.C. They can span 10’-18’ distances. In comparison, steel joists range from 12’-60’ spans. Wood Joists are part of a structural subsystem and with the addition of sheathing (wood subflooring) becomes a strong structural diaphragm to transfer loads to shear components. Joists must be specified according to loads, spacing, species and defection allowance. Bridging is required with joist of 6” or deeper depth at every 8’.
Wood sub flooring is a structural component and consists of wood panels of plywood/OSB or wafer board. These panels are less susceptible to shrinkage than lumber. The panels are laid perpendicular to the joists with nails and glue (eliminates squeaks and creeps), have smooth surfaces for finished flooring and serves as an impact load resistant. Decking is usually laid over the sub flooring. Decking can be single (weakest), double or a continuous (strongest) span.
Wood plank and beams are used to distribute loads evenly by spacing elements in a grid pattern that aligns with other load bearing structure units. This system can be used as heavy timber construction if it uses fire resistive exterior walls (brick/ concrete). Disadvantages of the wood plank system include sound transmission and lack of concealment for MEP’s and insulation.
Wood beams are supported by load bearing structural elements such as masonry walls, timber, steel and concrete columns.
Steel beams and joists are also spanning units. Similar to wood framing, steel members come in nominal sizes and shapes. Steel open web joists can span distances from 12’-60’ respectively at 2’-10’ O.C. spacing. Other deeper steel joists (LH & DLH) can span from 36’-144’. Steel beams can be connected with steel angles, stiffer palters, bolts and/or welds. Similar to lumber, steel beams and joists must increase its depth to span longer distances. Some steel beams were made to alleviate this problem. One good example is the castellated beam which is deeper and longer but not heavier. Steel joists works well with rectangular one-way systems, masonry bearing walls, steel beams and suspended ceilings. These joists can support decking of wood, precast panels or concrete fill toppings. Bridging is also needed at 10’-20’ O.C. Connections to steel must resist shear and moment deflections. In summary, all spanning elements must be calculated in proportion to the distance spanned and load carrying capacity. They must be paired with vertical elements for load distribution and equilibrium.
Reading Summary
Reading 6 focuses mostly on building materials, Ching talks about different materials like Bricks/CMUS and how they are bonded, Wood, Steel and Concrete, concrete reinforcement. Bricks come in different shapes sizes and compositions (same with cmu) Bricks can be made with soft mud all the way to water struck construction, the main difference between all the brick types is how the brick is being assembled and what types of conditions in going to be used in like SW bricks are tailored more into being resistant to severe weather like rain and snow which make brick deteriorate faster, CMU or concrete masonry units are on a similar level with brick, they are pre cast with cement, water and aggregate and are poured into cast to take on a specific shape which is determined by the function the unit has to fulfil, CMU also has different grade Levels like N OR S which is for loadbearing but one is meant for exterior use because its weather protected while the other is more for walls exposed to moisture, Wood and steel are 2 very different building elements, Wood can range from being hard to soft and is mainly used for manufacturing things such as doors, winds, and mill work. Wood is categorized by Yard lumber or Shop wood (lumber/timber) the wood can have different grades which are made up from moisture content and species of wood. Steel beams are very versatile because they have good tensile and compressive property’s, the most common shaped steel beam is called the Wide Flanged beam, steel could be welded or riveted together, and its strength depends on the size of the steel as well as the connection it has with the other members. And lastly we have concrete, concrete is a very strong material which is made of cement and various minerals, it has very good compressive resistance but is very weak in tension just like bricks, Steel reinforcement is placed inside of concrete to give it more structure and add tensile force to the concrete, cement rages from category 1-5 . if concrete is reinforced the steel rods that are inside must be protected form the elements to prevent rust which will deteriorate the concrete that’s around it.
Ching explains in detail building materials such as wood and steel. The wood is malleable and compressible, shape-changing and lightweight, but the steel shows better results in terms of firmness and fire resistance. Steel with SWC and tubing three shapes. It also talks about different ways of building wood and steel
