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Double-Skin Façade Case Studies
Published in Mary Ben Bonham, Bioclimatic Double-Skin Façades, 2019
With the louver blinds relegated to the upper zone of the façade on each floor, a sizeable externally mounted solar control device was necessary to shade glazing in the lower zone. Laminated glass ‘visors’ extend 1,976 mm (6.5 ft) to manage summer heat gain and mitigate potential glare conditions for the reading areas located alongside each level of the façade. The visor glass tilts slightly back toward the façade directing rain or melting snow into the grate rather than the grass. A separate 254 mm (10 in.) laminated glass panel positioned over the main visor panels blocks light from entering a gap between the visor and the façade. The thick glass panels, made from two 10 mm (6/16 in.) fully tempered glass panes joined by a 1.9 mm (1/16 in.) PVB interlayer, are bolted with steel angles to steel plate fins. The fins are an extension of the DSF’s welded ladder truss frame and transfer the visor’s weight through to core of the truss. The architects selected a gray tint for the visor glass to effectively reduce solar transmission while simulating the appearance of clear glass.17
Engineering, machines, power, and energy
Published in Jill L. Baker, Technology of the Ancient Near East, 2018
To level an area, the Egyptians used an A-frame level with a plumb bob (Figure 7.12). The horizontal part of the A-frame was marked at specific intervals, and when the legs of the frame were placed on a surface, the pendulum of the plumb indicated whether the surface was flat. Leveling using the A-frame appears to have been nearly exact, for the pavement upon which the Great Pyramid at Giza sits is almost completely flat, with a slope of only 6 millimeters east to west and 14 millimeters north to south, which covers a distance of 230 meters in each direction (Lyons 1927:136). The A-frame was also used to level the stone courses of the pyramids and other buildings such as temples, palaces, and homes, as well as walls. Water also may have been used to level a surface. This could be achieved by filling a chiseled trench with water, marking the waterline, which would have been level, emptying the trench, then measuring down to see if the bottom was level. Additionally, a container with level horizontal markings also could have been used.
Analysis of Statically Indeterminate Structures by the Force Method (Flexibility Method or Method of Consistent Deformation)
Published in Kenneth Derucher, Chandrasekhar Putcha, Uksun Kim, Hota V.S. GangaRao, Static Analysis of Determinate and Indeterminate Structures, 2022
Kenneth Derucher, Chandrasekhar Putcha, Uksun Kim, Hota V.S. GangaRao
This method is applicable to any kind of beam, frame, or truss. It is to be noted that beam and frame structures are predominantly bending (flexure) structures, while trusses are predominantly direct stress structures (tension or compression) in nature. The truss members are not subjected to bending in theory, even though joints freeze and exert small moments on to a member. In other words, all loads are axial.
Improved Explicit Integration Algorithms for Structural Dynamic Analysis with Unconditional Stability and Controllable Numerical Dissipation
Published in Journal of Earthquake Engineering, 2019
Chinmoy Kolay, James M. Ricles
To demonstrate that the proposed MKR- method is well suited for complex nonlinear problems in earthquake engineering, consider the two-story steel moment resisting frame (MRF) shown in Fig. 10. The frame members are not designed according to a building code; nevertheless, it features characteristics that are typical of a seismically designed moment resisting frame, for example, strong columns and weak beams. The beams and columns of the MRF are modeled using nonlinear displacement-based beam-column fiber elements with five integration points (Gauss-Lobatto type) along the length of each element. At each integration point, the element sections (see Fig. 10 for the sizes) are discretized using 10 fibers through the depth of the web and 3 fibers through the thickness of each flange. The steel material behavior is assumed to be bilinear-plastic with elastic modulus GPa, yield stress MPa, and a post-yield modulus of . The gravity load resisting system associated with the MRF is modeled using a lean-on column which is composed of linear elastic beam-column elements ( m2, m4) with second-order effects. At each floor level, the seismic masses are lumped at the lean-on column, nodes. These nodes are constrained in the horizontal direction with the center node of the respective floor beams to simulate the rigid floor diaphragm action as depicted in the figure. The system mass matrix is developed considering these lumped masses and using a consistent element mass matrix formulation based on the self-weight of the members. In total, the structure has 33 nodes, 32 elements, and 91 DOFs. The first two modal periods of the system are equal to s and s, respectively. The inherent damping in the system is modeled using a form of non proportional damping (NPD) model where the damping matrix is composed of a mass proportional part and an initial stiffness proportional part that excludes the stiffness contribution of the elements undergoing significant inelastic deformations. To this end, the stiffness contributions of the two elements at each end of the two floor beams (see Fig. 10) are excluded and the damping matrix is formed to assign 2% damping to the first and second modes of the system. A detailed discussion regarding the choice of the NPD model can be found in Kolay et al. [2015] and Kolay and Ricles [2016].