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Construction materials and main structural elements
Published in Pere Roca, Paulo B. Lourenço, Angelo Gaetani, Historic Construction and Conservation, 2019
Pere Roca, Paulo B. Lourenço, Angelo Gaetani
According to local experience, ancient designers were sometimes able to recognize the different capacity of soil layers, and, in many cases, they deepened the foundation until reaching an assumed adequate stratum. This approach is at the basis of the definition (even in modern times) of shallow and deep foundations, where the former consisted of stones (blocks or rubble) and brick masonry (in some cases mixed with reed, small tree branches, cow skins or other additions), whereas the latter could be built, for example, by means of wooden piles. As shown in Figure 3.11a,b, the shallow foundations can be divided into two groups, namely, isolated (for single column footing) and continuous (for wall footing). The two-dimensional extension of the continuous foundation leads to a two-way beam and slab, or flat plate raft.
Foundations, ground slabs, retaining walls, culverts and subways
Published in Charles E. Reynolds, James C. Steedman, Anthony J. Threlfall, Reynolds's Reinforced Concrete Designer's Handbook, 2007
Charles E. Reynolds, James C. Steedman, Anthony J. Threlfall
When the load on a strip footing is distributed uniformly over the whole length, as in the general case of a wall footing, the principal effects are due to the transverse cantilever action of the projecting portion of the footing. If the wall is of concrete and built monolithically with the footing, the critical bending moment is at the face of the wall. If the wall is of masonry, the maximum bending moment is at the centre of the footing. Expressions for these moments are given in Table 2.83. If the projection is less than the thickness of the base, the transverse bending moment may be ignored but the thickness should be such that the shear strength is not exceeded. Whether or not a wall footing is designed for transverse bending, longitudinal reinforcement is generally included, to give some resistance to moments due to unequal settlement and non-uniformity of bearing. In cases where a deep narrow trench is excavated down to a firm stratum, plain concrete fill is normally used.
Experimental Research on Seismic Performance of Precast Concrete Shear Walls with a Novel Grouted Sleeve Used in the Connection
Published in Journal of Earthquake Engineering, 2023
Qing Zhi, Zhijun Yuan, Yongfeng Zheng, Lu Jia, Zhengxing Guo
Figure 18 shows the local deformation at the wall-footing joint interface of the shear walls including the crack width and compressive deformation. The crack width at the wall-footing joint interface (namely, at the bottom end of the sleeve) resulted from the bond slip of the spliced bar in the sleeve and strain penetration in the foundation. In addition, the bond strength between the bedding mortar and the wall-footing layer was poor compared with monolithic concrete. Therefore, the crack width of the wall-footing joint was obviously larger than that at the upper end of the sleeve. Furthermore, the crack widths of the wall-footing joint of the precast specimens were significantly larger than that of cast-in-situ specimen W0. In Fig. 18b, due to the low strength of the bedding mortar of W2, the bedding mortar was almost completely crushed during the test resulting in large compressive deformation in the wall-footing joint. The compressive deformation of the precast joint with high strength grout (W3) was relatively small.
Identifying Dynamic Response of a Twenty-Story Instrumented Building to 2018 M7.1 Anchorage, Alaska Earthquake and Its Aftershocks
Published in Journal of Earthquake Engineering, 2022
The Atwood Building, located northwest downtown Anchorage Alaska, is an iconic twenty-story moment-resisting steel frame office structure with a basement used as a parking garage. The building was designed according to the 1979 Uniform Building Code (ICBO 1979) and constructed in 1980. It has a square footprint of 39.6 m (130 ft) with a square concrete core of 14.6 m (60 ft). The total height of the building is 80.54 m (264.2 ft). The building’s reinforced concrete shallow foundation consists of a 1.52 m (5 ft) thick mat under the center core with a perimeter wall footing connected with grade beams. The instrumentation consists of a 24-bit IP-based data logger and an array of 32 accelerometers distributed on 10 levels (Fig. 2), including basement, 1st (ground), 2nd, 7th, 8th, 13th, 14th, 19th, 20th, and roof. This accelerometer array records 200 samples-per-second from each channel. Further details on the structure and instrumentation can be found in Wen and Kalkan (2017).
Structural window frame for in-plane seismic strengthening of masonry wall buildings
Published in International Journal of Architectural Heritage, 2019
Jorge Miguel Proença, António S. Gago, André Vilas Boas
The unreinforced masonry wall (UMW) and the reinforced masonry wall (RMW) underwent cyclic displacement-controlled testing to failure. The tests were carried out with a vertical stress of 0.2 MPa (126 kN), representing an average vertical stress due to dead loads at mid-height of an old masonry building. Thus, both walls were initially subjected to a vertical compression load which was kept constant for the remainder of the test. A stiff beam on the top of the walls was used to ensure a uniform distribution of the vertical load and a set of steel rollers were placed on the top of the walls to allow its horizontal displacement (Figure 6, the load being applied by the vertical jack). The horizontal load was transmitted to the top of the wall by means of a system of steel plates that was firmly connected with high strength steel (HSS) threadbars. In order to prevent the wall footing from sliding, the reinforced concrete footing was fixed to the strong floor and reaction wall by a system of steel beams and horizontal pre-stressed HSS threadbars. The vertical load application system and a lateral frictionless guiding system were attached to a transverse steel frame (not shown in Figure 6).