Vertical And Horizontal Loads Due To
Vertical And Horizontal Loads due Th
Compute the values requested using the basic floor framing plan shown in the accompanying figure. Consider floor live-load reductions following the provisions of ASCE 7 as appropriate. For purposes of these problems, assume that this is the uppermost floor in a multistory office building. Also assume that it has a one-way slab behavior.
a. Load on column B3 contributed by this floor if the floor live load is 150psf.
b. Load on column A3 contributed by this floor if the floor live load is 75 psf.
c. Load on column A1 contributed by this floor if the floor live load is 100psf.
d. Load on an interior floor beam if the floor live load is 75psf.
e. Load on Girder B2-B3 if the floor live load is 50 psf.
2. The loading for a single frame-line of a three story building is given in the figure. The roof is subjected to a snow load and a dead load, while the two upper floors are subjected to floor live load and dead load. Using the tributary approach and without taking any reductions, find the following:
a. The total dead load, live load and snow load present in column B between the second and third floors.
b. Sketch the loading diagram including all relevant loads for the transfer girder located at the second floor.
c. The total dead load, floor live load, and snow load present in column A between the ground and the second floor.
d. Using the strength-based load combinations, find the total design axial load that should be used for the column described in part c. (Assume the floor live load results from a load less than 100 psf.)
3. Compute the values requested using the basic floor/roof framing plan. The building consists of five levels as shown. If live load reductions are considered, use the appropriate provisions given in ASCE 7.
a. Assume W = 20 ft and D = 48 ft and that the slab behavior can be classified as a two-way slab. If the dead load for the roof is 22 psf, compute and sketch the load diagrams for B1, B3, G3, and G4 located in the roof. (Be careful of the opening.)
b. Assume W = 20 ft and D = 48 ft and that the slab behavior can be classified as a two-way slab. If the dead load for the roof is 22 psf, compute and sketch the load diagrams for B1, B2, G1, and G2 located in the roof. (Ans: point loads on G1 = 1848 lb, point loads on G2 = 3696 lb)
c. Assume W = 20 ft and D = 30 ft and that the slab behavior can be classified as a one-way slab. If the unreduced floor live load is 50 psf, compute and sketch the load diagrams for G1, G2, G3, and G4 located in the fourth floor. Take appropriate reductions. (Ans: point loads on G1 = 3593 lb, point loads on G2 = 5625 lb)
4. The senior engineer working on a two-story office building project has laid out a framing plan to be used for the first floor and roof level. The box with an a— in the plan view represents an opening in the floor and roof for the elevator. The senior engineer anticipates using a concrete slab supported by steel beams and girders. Before we can begin to design the members, we need to know the idealized load on each member due to each type of load.
a. We are tasked with finding the idealized live load. For preliminary design of the members, we can ignore the corridors and consider the entire floor to be offices. Let’s start with the idealized live load on girder B3-B4 for level 1 (first floor).
b. The maximum likely snow load on the roof is 20 psf. Our task is to find the idealized snow load on beam A2-B2 for level 2 (the roof).
c. A more experienced engineer on the team anticipates the floor and roof to be 12 inches thick. The superimposed dead load (weight of flooring, ceilings, lights, ducts, etc.) will be about 10 psf on the floor and roof. Initially let’s assume each beam and girder has a self- weight of 75 plf. Our task is to find the idealized dead load on girder A3-B3 for level 2, including its own self-weight.
5. We are to design the lateral load-resisting system for a building with a high roof. The senior engineer has already decided that the outer walls perpendicular to the wind will be the lateral load-resisting elements (e.g., the beige walls will resist wind from the left in the photo). The senior engineer has also concluded that the best way to transfer the wind pressure to the outer walls is by purlins. Therefore, the outer skin of the wall touches only the slab-on-grade and the purlins. Before we can analyze and design the purlins, we need to determine the idealized line load on each purlin due to the wind. The wind generates a pressure of 950 Pa.
6. Our team is designing the lateral load-resisting system for a two-story office building. To do so, we need to determine the wind loads on the lateral load-resisting elements. At this preliminary stage, let’s consider the floor and roof diaphragms to be flexible, and consider the wind pressure to be uniform. Note that the south and east walls have been cut away so that we can see the system supporting them.
a. When the wind blows from the south, it creates a uniform pressure of 25 psf on the south elevation. i. Our job is to convert the applied wind pressure into line loads that act at each diaphragm level on the windward side. ii. Then we are to convert the line loads into point loads that act at the locations where the diaphragms meet the lateral load-resisting elements.
b. When the wind blows from the east, it creates a uniform pressure of 30 psf on the east elevation. i. Our job is to convert the applied wind pressure into line loads that act at each diaphragm level on the windward side. ii. Then we are to convert the line loads into point loads that act at the locations where the diaphragms meet the lateral load-resisting elements.
Paper For Above instruction
This comprehensive analysis covers multiple aspects of structural load calculations for a multi-story office building, focusing on vertical and horizontal loads, including dead loads, live loads, snow loads, wind loads, and their interactions with structural elements such as columns, beams, girders, and lateral resistance systems. The tasks include calculating specific load contributions on various structural members, sketching load diagrams, and determining idealized loads for preliminary design considerations, all aligned with relevant codes and standards such as ASCE 7.
Initial focus is placed on determining the load contributions to specific columns and beams based on given floor loads and configurations. For example, calculating the load on column B3 from a floor with a live load of 150 psf considers floor dimensions and load reductions per ASCE 7. Similarly, the load on column A3 with a 75 psf live load, and on column A1 with a 100 psf live load, are to be computed, taking into account the floor layout and tributary areas. Interior floor beams and girders are also analyzed for their loadings considering these parameters.
The second part involves analyzing a three-story structure where loads such as dead loads, live loads, and snow loads are distributed across the columns and girders, using tributary areas. The goal is to calculate the total loads in specified columns, sketch the load diagrams for transfer girders, and determine the total axial loads based on design load combinations, considering the absence of load reductions.
Further, the analysis extends to a five-level building with specific W (width) and D (depth) dimensions, where the behavior of slabs as two-way or one-way systems influences the load distribution on various members. Calculations include load diagrams and point loads for members like G1, G2, G3, G4, and their placement in the roof or fourth floor, considering dead load contributions, live load reductions, and slab behavior.
Additional considerations involve idealized loads on members due to various loads such as live loads on girders, snow loads on beams, and dead loads including self-weight calculations. These are necessary for preliminary design and for establishing load paths and member capacities.
The final part addresses the lateral load-resisting system, notably wind loads. It includes converting wind pressures (such as 25 psf from the south or 30 psf from the east) into line loads acting on diaphragms, and then further into point loads where these diaphragms connect to the lateral resistance elements like outer walls and purlins. The wind load analysis is crucial for designing effective lateral force-resisting systems to ensure structural stability under wind effects.
Overall, these tasks encompass a detailed set of structural load calculations essential for safe and efficient building design, emphasizing the importance of code compliance, load path analysis, and the integration of various load effects into comprehensive structural systems.