Comparison of Quantity of the Materials Between Rectangular and T-Beams

Structure is a big part among the other structure in the present especially in Cambodia. The structural concrete of building has many types such as a frame of column and connected beam, a frame of column and slab, a frame of retaining wall and slab, and many types. Among of these types of the building concrete structure, a frame of column and connected beam is the most popular for small building. In a frame of column and connected beam which slab is casted with a beam, the supported span of the beam is called Rectangular Section. However, the mid span can have different shape based on the assuming of designer. Due to this reason, the topic of the thesis under the title Comparison of Quantity of the Materials Between Rectangular and T-Beams is brought to study.

In this thesis, the design and analysis of structure is based on ACI 318-19and ASCE 7-16 for design load. The cost of materials and labor are also based in Cambodia.

The slabs thickness for designation are between 4𝑚𝑚 × 4𝑚𝑚 to 8𝑚𝑚 × 8𝑚𝑚 and for live loads, there are 2𝑘𝑘𝑘𝑘/𝑚𝑚2, 2.5𝑘𝑘𝑘𝑘/𝑚𝑚2, 3𝑘𝑘𝑘𝑘/𝑚𝑚2, 5𝑘𝑘𝑘𝑘/𝑚𝑚2 and 12𝑘𝑘𝑘𝑘/𝑚𝑚2. The
slabs thickness and beams section are must be economical and safety.

The process of the design is start from gathering loads on slab, beam and then determine bending moment and shear which based on ACI code. After that, the calculation of nominal flexural strength will start from the end section of beam and then the center section as rectangular beam and T-section beam. The estimation of materials and labor cost, will be calculated at the end of the process.

As expected, the cost of materials and labors in the middle section of rectangular beams are more expensive than the T-section beams. In all cases of the variable live loads, we found that the cost of materials and labors for T-beams were more profitable then rectangular beam at a rate of 1% to 2% depending on the amount of rebars. The rate of the profit can also exceed 2% when the amount
of rebars are increased.