BEHAVIOR OF STEEL PLATE-CONCRETE COMPOSITE SHEAR WALL UNDER CYCLIC LOADING

Steel-Concrete composite shear wall has become popular recently as it compensates for the disadvantages of concrete and steel plate shear walls and combine the advantage of both. However, there is no detail study that identifies the most critical parameters. This study aims at investigation of steel plate-concrete composite shear wall behavior under cyclic loading with variables such as concrete strength, grade of steel plate, total number of tie constraints and thickness of steel plate. ABAQUS/Standard is used for numerical modeling in this study. As the concrete strength decreases from 86.1Mpa to 45Mpa, the load capacity declined by 11.76% and higher stiffness was recorded in specimen with higher grade of concrete. The ductility factor is inversely proportional to grade of concrete from 86.1Mpa to 60Mpa which increases from 4.26 to 4.68 and the ductility factor of specimen with 45Mpa strength is recorded as 3.81. The energy dissipation capacity is directly proportional to the grade of concrete used. Using high grade steel plate increases the lateral load capacity significantly and exhibited more ductile behavior. Specimen with S355 steel grade exhibited 14.01% increment of the average load capacity while the specimen with S245 steel grade has shown reduction by 9.21%. Similarly, the ductility factor and energy dissipation capacity of specimen with variable grade of steel are directly proportional. Reduction of tie constraints has no significant effect on the behavior in this study due to high confinement effect of concrete by surrounding steel plate. Specimens with thicker steel plate exhibited good energy dissipation capacity.

Effect of Building Configuration on Overstrength Factor and Ductility Factor

It is important for the structure to be economical and still have a high level of life safety. The lateral force sustained by the structures during a large earthquake would be several times larger than the lateral force for which the structures are designed. This is opposite to the fact that design loads such as gravity in codes are usually higher than the actual anticipated load. It is based on the probability that the occurrence of large earthquakes is quite rare and the capacity of the structure to absorb energy. The co-factors of response reduction factor which is the overstrength factor and ductility factor reduce the design horizontal base shear coefficient. A total of 36 low-rise residential buildings having different storey, bay and bay lengths are selected and analysed in this paper. NBC 105: 2020 is selected for the seismic design of RC buildings while provision provided in FEMA 356:2000 is used to carry out non-linear pushover analysis. The results indicated that between the different structures, the value of overstrength factor and ductility factor has a high deviation.

Structural Response Prediction for Damage Identification Using Wavelet Spectra in Convolutional Neural Network

If damage to a building caused by an earthquake is not detected immediately, the opportunity to decide on quick action, such as evacuating the building, is lost. For this reason, it is necessary to develop modern technologies that can quickly obtain the structural safety condition of buildings after an earthquake in order to resume economic and social activities and mitigate future damage by aftershocks. A methodology for the prediction of damage identification is proposed in this study. Using the wavelet spectrum of the absolute acceleration record measured by a single accelerometer located on the upper floor of a building as input data, a CNN model is trained to predict the damage information of the building. The maximum ductility factor, inter-story drift ratio, and maximum response acceleration of each floor are predicted as the damage information, and their accuracy is verified by comparing with the results of seismic response analysis using actual earthquakes. Finally, when an earthquake occurs, the proposed methodology enables immediate action by revealing the damage status of the building from the accelerometer observation records.

Analytical Fragility Curves of Pile Foundations with Soil-Structure Interaction (SSI)

Pile foundations is a well-studied technique with many applications and its benefits on structures have been widely studied in the literature. In particular, the mutual effects of pile flexibility and soil deformability may significantly modify the seismic behaviour of superstructures. In order to consider the uncertainties that are connected with these issues, the paper applies the probabilistic-based approach of fragility curves by proposing three limit states based on ductility factor. Non-linear dynamic analyses were performed with OpenSees PL to assess the potentialities of three pile configurations founded on three cohesionless soil with different deformability.

Investigation on the Performance of Hybrid Fiber Reinforced Geopolymer Concrete Made of M-Sand under Heat Curing

Due to the elevating demand to replace the conventional cement concrete with any other building material, there has been a continuous effort to promote the properties of geopolymer concrete. The objective of this paper is to reduce the brittleness of geopolymer concrete. This research paper goes for exploring the impact of high and low young’s modulus fiber in geopolymer concrete made of M-sand. Mix proportion of various materials is based on the Rangan’s proposed Mix design. Geopolymer concrete used in this investigation is the Fly ash – Ground Granulated Blast Furnace Slag blend based. Concoction of NaOH solution and Na2SiO3 solution is used as the alkali solution. Sine 80 percent of the source material is flyash, the specimens are exposed to heat curing. Fresh property and hardened characteristics like workability, ductility factor, compressive, split tensile, flexural and impact strength are assessed in this study. Significant increase in the engineering properties is observed with respect to both the fibers. This work unveils lot of potential in the vicinity of Geopolymer concrete.

DUCTILITY FACTOR OF REINFORCED CONCRETE FRAME WITH WEAK BEAM-COLUMN JOINT

Code requirements are usually fulfilled during the design of a building. On the other hand, reinforced concrete (RC) frames (particularly in the developing regions of the world) are found deficient due to unregulated constructions. Majority of such deficient structures lack shear reinforcement in beam-column joints. Collapse of these deficient buildings (as a result of limited ductility) triggered many socio-economic and human losses which is evident from recent earthquake disasters. This paper presents an experimental study which was conducted on a 1:4 reduced scale three-storey RC special moment resisting frame (SMRF) lacking shear reinforcement in the beam-column joints. The lack of confinement bars causes shear hinging of joints that reduces the displacement ductility of the frame. Shake-table tests were conducted on test model that was subjected to acceleration time history of 1994 Northridge earthquake, having a peak ground acceleration of 0.57g. The acceleration was linearly scaled to multiple levels and to sinusoidal base excitations of various frequencies and displacements. Moderate to severe damage at each storey level was observed in the joint panels due to the lack of lateral reinforcing ties in the joints. The data obtained from shake table tests were processed and analysed to develop a lateral force-deformation capacity curve, which was bi-linearized as an elasto-plastic curve to compute various response parameters of frame. The ductility factor (Rμ) of the tested model was found to be equal to 1.95, which is thirty-five percent less than the code recommended value of Rμ for RC SMRF structures.

Seismic performance of a load-bearing prefabricated composite wall panel structure for residential construction

To improve both seismic performance and thermal insulation of low-rise housing in rural areas of China, this study proposes a load-bearing prefabricated composite wall panel structure that achieves appropriate seismic performance and energy efficiency using field-assembled load-bearing prefabricated composite wall panels. A 1:2 scale prototype built using load-bearing prefabricated composite wall panel is subjected to quasi-static testing so as to obtain damage characteristics, load-bearing capacity and load–displacement curves in response to a simulated earthquake. As a result, seismic performance indicators of load-bearing capacity, deformation and energy-dissipating characteristics, are assessed against the corresponding seismic design requirements for rural building structures of China. Experimental results indicate that the earthquake-resistant capacity of the prototype is 68% higher than the design value. The sample has a ductility factor of 4.7, which meets the seismic performance requirement mandating that the ductility factor of such concrete structures should exceed 3. The design can be further optimized to save the consumption of material. This shows that the load-bearing prefabricated composite wall panel structure developed here has decent load-bearing capacity, ductility and energy dissipation abilities, a combination of which is in line with the seismic design code. A new construction process proposed here based on factory prefabrication and field assembly leads to a considerable reduction of energy consumption.