Analysis of Multistory Buildings With Stub Column In Different Seismic Zones In India – A Review

Construction of building requires proper planning and management. Buildings are subjected to various loads such as dead load, live load, wind load and seismic load. Seismic load has extreme adverse effect on building so it is necessary to perform seismic analysis. This paper explains about the response of building when it is subjected to seismic load, this response can be shown by story drift and base shear. Behavior of buildings with stub columns is analyzed and the results are compared with buildings without stub columns. Seismic analysis has been performed on (G+7) buildings located in seismic zones 2,3,4&5 using ETABS software. Analysis has been performed according to IS 1893:PartI (2002).The storey drift and design base shear are evaluated and compared. Pushover analysis was performed and the results were compared.

Flexural Behaviour of Different Stiffener Section Area on Full Height Rectangular Opening Castellated Steel Beam

Vierendeel is one of failure mechanisms in a castellated steel beam. Vierendeel mechanism is the main failure that occurs in a full high rectangular opening castellated beam. Vierendeel decrease castellated flexural capacity compare to the original wide flange section beam. One solution to prevent the vierendeel mechanism is by installing a diagonal stiffener in form of a steel bar on a castellated beam. The research’s purpose is finding the effect of different size of steel bar diameter on the flexural capacity. Four different sizes of steel bar diameter used in this research: 10 mm, 12mm, 16 mm, and 19 mm. Castellated beam flexural capacity is analysed with the method of truss analysis and pushover analysis. This study shows it can be infer that the bigger size of steel bar diameter does not always determine the higher flexural capacity of the castellated beam. Optimum value of the beam’s flexural capacity is affected by the strength of the flange section. The largest increment of flexural capacity between original wide flange compare to the castellated beam is 139.4% by using 16 mm diameter of the diagonal stiffener.

Special Moment Resistant Steel Buildings

The seismic response of special moment-resisting frames (SMRF), buckling restrained braced (BRB) frames and self-centering energy dissipating (SCED) braced frames is compared when used in building structures many stories in height. The study involves pushover analysis as well as 2D and 3D nonlinear time history analysis for two ground motion hazard levels. The SCED and BRB braced frames generally experienced similar peak interstory drifts. The SMRF system had larger interstory drifts than both braced frames, especially for the shortest structures. The SCED system exhibited a more uniform distribution of the drift demand along the building height and was less prone to the biasing of the response in one direction due to P-Delta effects. The SCED frames also had significantly smaller residual lateral deformations. The two braced frame systems experienced similar interstory drift demand when used in torsional irregular structures.

Extension of The Improved Upper-Bound Pushover Analysis For Seismic Assessment of Steel Moment Resisting Frames With Setbacks

Pushover analysis technique is a key tool for the performance-based seismic design that has been largely adopted in the new generation of seismic codes. Therefore, more precise and reliable performance predictions are highly demanded. Improved upper-bound (IUB) pushover analysis is one of the advanced nonlinear static procedures (NSPs) that has been recently developed. This procedure estimates adequately the response of regular and tall buildings. In this study, IUB is extended to assess the seismic response of irregular buildings with setbacks. To this end, an adjustment of the IUB lateral load distribution is implemented by integrating a third mode of vibration to control the response of these complex buildings. Fifteen multi-storey steel frames with different types of setbacks including a reference structure are used to test the accuracy of the proposed procedure by comparing its results to those from other NSPs and the nonlinear time history analysis (NLHA). The findings show the superior capacity of the extended IUB in predicting the seismic response of buildings with different levels and types of setbacks.

On Factors behind the Reasonable Failure Mode of Concrete-Filled Circular Steel Tubular Composite Frame

As the most basic structure, the concrete-filled steel tubular (CFST) frame has been widely used in various structures and systems. Compared with conventional reinforced concrete structures and steel structures, CFST structures in strong earthquake showcase more complicated strength and deformation behavior because there are many factors underlying the failure mode. Furthermore, according to the specifications at home and abroad, the corresponding design method to achieve reasonable failure modes for CFST structures has not been clarified. Based on a destructive test on steel beam-CFST plane frames under constant axial load and lateral load, the fiber mode method and solid element model method are adopted to simulate the failure process of the test frames. Based on finite element model simulations and tests, the fiber model method is proposed to carry out the pushover analysis on the CFST frame structures. The factors behind the reasonable failure mode of steel beam-concrete-filled circular steel tubular (CFCST) frame structures are analyzed. Furthermore, the law and influencing factors behind the ratio of flexural capacity of column to beam, the ratio of line stiffness of beam to column, and the ratio of axial compression on the deformation, bearing capacity, and failure modes of the structure are discussed. Some suggestions on the design of reasonable failure mode of steel beam-concrete-filled circular steel tubular (CFCST) frame structures are proposed.

Evaluasi Struktur Bangunan Pasar Inpress Blok IV Gedung B dengan Metode Pushover

Inpres market block IV Pasar Raya Padang is not designed as a shelter building, but is designated as a vertical evacuation site when a tsunami occurs. This study aims to evaluate the structural performance of Inpress market block IV zone B. The method used for this research is the pushover analysis method. According to FEMA P-646/2019, vertical evacuation refuge structures are included in tsunami risk category IV, based on the risk category the maximum performance level is at the Immediate Occupancy (IO). For loads on buildings, refer to SNI 1727:2020 and SNI 1726:2019 for earthquake loads. For the calculation of the capacity of concrete structural elements, refer to SNI 2847:2019. Structural analysis was carried out using the SAP2000 version 16. After analysis, based on performance points, drift ratio that occur due to earthquake loading in X-direction and Y-direction are 0,05875% and 0,0067%. The maximum total drift that occurs is smaller than that required by ATC-40 for the Immediate Occupancy performance level, which is 1%. Thus, the structure performance level is Immediate Occupancy. This means that the Inpress market block IV building is still strong enough against earthquake loads.

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.

Seismic Performance Assessment of a Moment-Frame Reinforced Concrete Building Typology

This study covers the application of Static and Dynamic nonlinear analysis to an old moment-frame reinforced concrete building. The case study selected is a template one designed in 1982 without shear walls and built throughout Albanian region in the communism era using old standards (KTP 2-78). For the capacity calculation, Pushover analysis is performed using an inverse triangular load pattern. The demand calculation is conducted using Incremental Dynamic Analysis (IDA) as a method which provides the response behavior of the structure from the elastic range until collapse. For the dynamic analysis is used a set of 18 earthquakes with no marks of directivity. Limit states are defined for both Pushover and IDA based on the FEMA 356 guidelines. The mathematical model is prepared in the environment of Zeus-NL, a software developed especially for earthquake applications. The parameters defined for the IDA analysis are 5% damped first mode spectral acceleration (Sa(T1,5%)) for the intensity measure (IM) and maximum global drift ratio (ϴmax) for the damage measure (DM). In addition, limit states are selected for the pushover curve as Immediate Occupancy (IO), Life Safety (LS) and Collapse Prevention (CP). Similarly, for the IDA curve the limit states are selected as IO, CP and Global Instability (GI) based on FEMA guidelines. Furthermore, IDA curves are summarized into 16%, 50% and 84% fractiles as suggested in the literature. Additionally, a comparison between Pushover and IDA median (50% fractile) is shown from the same graph to illustrate the correlations between performance levels. Finally, structural performance is interpreted based on the outcomes.

Slenderness Ratio and Influencing Parameters on the NL Behaviour of RC Shear Wall

Shear walls are very efficient structural elements to resist lateral seismic disturbance. Despite the aforementioned seismic performance, recent investigations report that they have suffered from significant structural damage after recent seismic activity, even for those complying with seismic provisions. These deficiencies in resistance and deformation capacities need to be explored. This study considers the influence of plastic length Lp, concrete compressive strength f_c28, longitudinal reinforcement ratio ρl, transverse reinforcement ratio ρsh, reduced axial load ν, confinement zone depth CS and focusing on the geometric slenderness λ. The parametric study has been conducted through NL pushover analysis using Peform3D software. The chosen coupled shear-flexure fiber macro model was calibrated with well-known cyclic experimental specimens. The paper points out the discrepancy between the two well-known codes EC8 and ASCE/SEI 41-13. In fact, the value of the slenderness ratio (λ) that trigger the beginning of a purely flexural behaviour recommended by EC8 (λ>2) is very different from the value of the ASCE/SEI 41-13 (λ>3) without accounting for the effect of the reduced axial force. Finally, it was found that RCW capacities are very sensitive to f_c28, ν, ρl, Lp and less sensitive to ρsh and CS. However, (λ) is the most decisive factor affecting the NL wall response. A new limit of slenderness and appropriate deformations of rotations are recommended to provide an immediate help to designers and an assistance to those involved with drafting codes. Doi: 10.28991/cej-2021-03091777 Full Text: PDF