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Preliminary design
Published in Hassan K. Al Nageim, T.J. MacGinley, Steel Structures, 2017
Hassan K. Al Nageim, T.J. MacGinley
Typical dead load values for various types of construction are required. These are available from hand books. Imposed loads are given in the code, see Section 2.3.1. Some comments on load estimation are as follows:Most loads are distributed. Beam and column reactions are point loads. Floor loading is expressed as equivalent uniform loads.Loads are assessed on the tributary floor area supported by the member.Loads are cumulative from roof down. Imposed loads are reduced depending on the number of floors involved.Wind loads generally act horizontally, but uplift due to suction is important in some cases.The structure is taken to be pin jointed for load estimation.
Design Loads
Published in Syed Mehdi Ashraf, Practical Design of Reinforced Concrete Buildings, 2017
Floors and roofs have uniform density, and their weights are expressed in terms of weight per unit area (psf). They are designed for this dead weight. Loads of finishes are also applied in the design of floors and roofs. The loads are distributed to their supports using the geometric concept of tributary area. The supports for floors and roofs could be walls, beams, or columns. Walls are used to support floors and roofs in the load-bearing walls structural system. In the framed systems, loads of floors and roofs are transferred to beams and from the beams to the columns. In the flat-plate system, loads of floors and roofs are directly transferred to the columns. A combination of these three systems can also be used to design buildings.
Formulating a site specific support system design methodology
Published in Ernesto Villaescusa, Christopher R. Windsor, Alan G. Thompson, Rock Support and Reinforcement Practice in Mining, 2018
A methodology is proposed to design for maximum stable hangingwall spans between adjacent support units. The design procedure consists of two phases, namely: Tributary area theory is applied to determine the load requirements of the support system.Maximum support spacing and stable spans between adjacent support units are determined by calculating the limiting equilibrium due to the two predominant failure mechanisms outlined in Sections 4.1 and 4.2, i.e. (i) beam buckling, or (ii) shear failure due to slip at the abutments.
Slab Vibration and Horizontal–Vertical Coupling in the Seismic Response of Low-rise Irregular Base-isolated and Conventional Buildings
Published in Journal of Earthquake Engineering, 2020
Jean C Guzman Pujols, Keri L Ryan
Additional model variations that include eccentric superimposed mass concentrations in addition to the penthouse loads were also defined. For both conventional and isolated models, superimposed mass concentrations of 2%, 5%, or 10% of the floor effective seismic weight were applied directly as area loads to shell elements at specific locations on each floor, which led to a corresponding increase in the total seismic weight of the building. All superimposed masses were applied either on the right or left half of the building in the longest plan dimension (see Figure 5), to induce eccentricity. Reflecting design strategies for nonuniform loading, mass locations were selected that spanned tributary areas of interior frame elements to maximize support and mid-span moments under gravity loading. Variations were considered with superimposed masses placed at alternating locations relative to the floor above and below, and at the same location in all floors. For instance, Figure 5(a) shows the additional mass locations applied on the left half of the conventional structure and alternating locations from floor to floor, with a span-to-span loading sequence that maximizes support moments. Similarly, Figure 5(b) shows the mass locations applied on the right half of the isolated structure and the same locations from floor to floor, with loading that maximizes mid-span moments. These case variations are coded “10%LA-” and “10%RS+”, respectively, where the mass percentage increment is indicated first, followed by “L” or “R” for left or right, “A” or “S” for alternating or same floor-to-floor location, and “-” or “+” for negative (support) or positive (mid-span) loading sequence, respectively. The same convention is used for all mass-eccentric cases presented hereafter, which all include the penthouse loads in addition to the superimposed masses.
Refinement and Validation of the Simple Lateral Mechanism Analysis (SLaMA) Procedure for RC Frames
Published in Journal of Earthquake Engineering, 2021
Roberto Gentile, Ciro del Vecchio, Stefano Pampanin, Domenico Raffaele, Giuseppina Uva
The story seismic weight is constant along the height and it is approximately equal to 1035 and 2017 kN for the 2- and 4-bays buildings, respectively. This is done by considering a concrete density equal to ρc = 25 kN/m3, a superimposed dead load Dsdl = 0.5 kN/m2 and a live load Q = 3 kN/m2 reduced by a factor ϕe = 0.3 [NZS1170.5, 2004]. The axial load on the columns is calculated based on tributary areas.