Simplified approach for the seismic analysis of precast girder bridges with gap

2021 ◽  
Author(s):  
E. F. Ayoub ◽  
M. Youakim ◽  
P. Nady

<p>Precast girder bridges are very attractive structural systems to bridge engineers due to their construction rapidity. In their deck arrangement a gap is introduced between the precast girders and the inverted pier cross head. Under longitudinal seismic effect the gap can be closed and the superstructure movement will be locked by the web of the pier cross-head. Usually a rigorous and sensitive non-linear time history analysis will be required for this type of structures. In this paper, a simplified approach will be introduced to estimate the base shear force transmitted to the bridge substructure under seismic loading. In the present approach the modelling of the elastomeric bearing element stiffness is modified in such a way that under earthquake loading the relative displacement between top level and bottom level of bearing equals to the gap value. The seismic analysis with slight, moderate and sharp earthquake accelerations is performed based on the response spectrum analysis as presented by AASHTO LRFD.</p>

Author(s):  
Harsh Joshi

Abstract: Due to sloping land and high seismically active zones, designing and construction of multistory buildings in hilly regions is always a challenge for structural engineers. This review paper focuses to establish a review study on the Possible Types of building frame configuration in the hilly region and he behavior of Such building frames under seismic loading conditions, and (3) The recent research and developments to make such frames less vulnerable to earthquakes. This paper concludes that the dynamics characteristics of such buildings are significantly different in both horizontal and vertical directions, resulting in the center of mass and center of stiffness having eccentricity at point of action and not vertically aligned for different floors. When such frames are subjected to lateral loads, due to eccentricity it generates torsion in the frame. Most of the studies agree that the buildings resting on slanting ground have higher displacement and base shear compared to buildings resting on plain ground and the shorter column attracts more forces and undergoes damage when subjected to earthquake. Keywords: Building frame configuration, Seismic behavior, Dynamic characteristics, Response spectrum analysis, time history analysis.


2020 ◽  
Vol 9 (1) ◽  
pp. 1986-1990

The structural response of any structure is the result of various dynamic phenomenon which lead to vibrations or shaking of the structure , depending on the duration of the ground motion, its frequency and time period. In the present work, dynamic analysis of a typical steel silo is done by using linear Time History Analysis and Response Spectrum method for earthquake Zone V as per Indian code. Two analyses are carried out namely, Time History Analysis (THA) and Response Spectrum Analysis (RSA) using STAAD.ProV8i software. The Load combinations are worked out as per IS-1893-2002. The results in terms of Fundamental natural period, Design Base shear, Lateral Displacements, are compared for the two different silo models considered in the present study.


Author(s):  
mahaboob subhani* Shaik ◽  
Budda Beeraiah

The improvements in (3D) three–dimensional underlying examination and processing assets have permitted the effective and safe plan of taller constructions. These constructions are the outcome of expanding metropolitan densification and financial suitability. The pattern towards continuously taller constructions has requested a move from the conventional strength based plan approach of structures to an emphasis on obliging the general movement of the design. Presently a day's supported cement (RC) divider outline structures are generally suggested for metropolitan development in zones with high SE danger. Presence of shear dividers bestows an enormous solidness to the sidelong power opposing arrangement of the RC building. Appropriate specifying of shear dividers can likewise prompt bendable conduct of such constructions during solid quake shaking. One of the remarkable boundaries impacting the shear divider (SD) SE (SE) conduct outline structures is the SD region proportion. In this manner a scientific examination is performed to assess the impact of Shear Wall Area to floor zone proportion (SW/FZP %) on the SE conduct of multistoried RC structures with delicate story at ground floor. For this reason, 12 structure plans that have Five, Eight and Twelve stories with SW/FZP % going somewhere in the range of 0.70% and 1.31% in the two ways are created. Here, the conduct of these plans under quake stacking is evaluated via doing Response Spectrum Analysis and Linear Time History Analysis utilizing primary examination programming E-TABS. Reaction Spectrum Analysis is finished by SE code IS 1893:2002. Straight Time History Analysis is completed by considering the three ground movement records to be specific Bhuj, Chamba and Uttarkasi. The primary boundaries considered in this investigation are the connection SW/FZP % has with base shear and rooftop dislodging, story uprooting and story float. The logical outcomes demonstrated that building plans with SW/FZP % equivalent to 1% acted sufficiently under tremor loads. Furthermore when the SW/FZP % expanded past 1% it is seen that the improvement of the SE presentation isn't as huge.


2017 ◽  
Vol 13 ◽  
pp. 20 ◽  
Author(s):  
Petr Čada ◽  
Jiří Máca

This paper investigates effects of the seismic load to a structure. The article describes main methods of the definition and practical application of the seismic load based on the Standard Eurocode 8. There was made a comparison of all methods using the same structure. A simple two-storeyed concrete 2D-frame with fixed joints was chosen. A one another model with rigid beams for some calculations was defined. The second model can be used for hand-calculations as a cantilever with two masses. The paper describes main dynamic properties of the chosen structure. Seismic load was defined by lateral force method, modal response spectrum, non-linear time-history analysis and pushover analysis. The time-history analysis is represented by accelerograms. There were made linear and non-linear calculations.


Author(s):  
Marame Brinissat ◽  
Rajmund Kuti ◽  
Zouhir Louhibi

Dynamic analysis is very important to better understand the performance of structural elements of a bridge. For this purpose, a seismic analysis of an Algerian highway bridge designed with the new Algerian seismic bridge regulation (RPOA -2008) was carried out using linear and nonlinear analyses. Therefore, response spectrum, time history analyses were performed to evaluate the seismic responses of the designed bridge. The performance of the designed bridge is assessed using 10 ground motion records. The proposed methodology allows an efficient comparison of the seismic response of the bridge in terms of base shear forces, bending moment and displacements. Finally, the paper concludes with a discussion of the specific outcomes.


2021 ◽  
Author(s):  
Sinem Tola ◽  
Joaquim Tinoco ◽  
José C. Matos ◽  
Elişan Filiz Piroğlu

<p>Turkey is located on active seismic fault lines. Having this major issue makes the seismic performance analysis a critical step to decide the safety or whether demolishing or reinforcing is more efficient. In this study, a seismic analysis comparison is performed on an existing steel structure via SAP2000 software. The seismic analysis method is Linear Time History Analysis. A comparison of results attained from dynamic analysis is obtained for an existing steel structure serving as a garage in Istanbul, Turkey. The results are demonstrated using graphics where base shear forces as well as lateral displacements obtained for two models are plotted for comparison.</p>


2022 ◽  
Vol 961 (1) ◽  
pp. 012072
Author(s):  
Mustafa Kareem Hamzah

Abstract Recent seismic events showed the importance of understanding the structural performance of RC column that can be predicted numerically. The accuracy of column performance depends on type of the analysis and representation of seismic effect. Therefore, in this paper a nonlinear time history analysis has been performed to assess the seismic performance of bridge column using fiber hinge concept with time integration method using sap2000 software. A long bridge RC column is utilized and subjected to seismic excitation. The column has been divided into different size and numbers of fiber to assess the accuracy of the analysis and time consuming to analyze each case of fiber hinges. In addition, this paper used three-time integration methods, Newmark, Hilber-Hughes-Taylor, and Chung & Hulbert to predict the most suitable method to be used in column seismic analysis. The time history displacement and base shear in addition to moment rotation of the column are the most important factors to evaluate the column seismic performance. The analysis results demonstrated that the most suitable time integration method is Hilber-Hughes-Taylor for such type of the analysis since it gives more stable base shear result than other two methods. Furthermore, the results indicated that the accuracy of seismic performance increased by number of fibers incremental. Moreover, the number of steel fibers should be equal to the number of bars with same area and location. The unconfined and confined concrete should be divided into small areas to get accurate prediction of column seismic performance.


CONSTRUCTION ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 93-101
Author(s):  
Saffuan Wan Ahmad ◽  
Muhammad Aimran Amzar Kamarudin ◽  
Wan Aniq Ridhwan Wan Ariffin

On the 5th June 2015, an earthquake hit Ranau, Sabah with a magnitude of 6.0 that caused 18 casualties and several injuries are one of the examples that show Malaysia is not safe from any seismic event. Most of the structure in Malaysia was designed not to include seismic action.  Furthermore, an area that has a high density of population such as in the central region (Klang valley) and several main cities in Malaysia has less available land to build landed housing and uses high-rise apartments as an alternative. High-rise buildings that are normally having problems with soft story mechanisms and plan irregularity which could lead to severe damage when earthquakes happen. This study aims to observe the response of high-rise buildings when under different earthquakes in the presence of shear walls. To achieve this objective two models were modelled and analyzed by using ETABS software, the one with a shear wall and the one with no shear wall. The methods used in this study were the response spectrum method and time-history analysis. In the end, the parameters observed were base shear, story stiffness, story drift, and story displacement. The observations highlighted that the effect of earthquake intensities shows a significant effect. The acquired results indicated that the building with the shear wall is more resistant and strong structures as compared to buildings without shear wall when undergoing seismic analysis.


2020 ◽  
Vol 2 (1) ◽  
pp. 40-47
Author(s):  
Anand Dev Bhatt

 Inter-storey drift is an important parameter of structural behavior in seismic analysis of buildings. Pounding effect in building simply means collision between adjacent buildings due to earthquake load caused by out of phase vibration of adjacent buildings. There is variation in inter-storey drift of adjacent buildings during pounding case and no pounding case. The main objective of this research was to compare the inter-storey drift of general adjacent RC buildings in pounding and no pounding case. For this study two adjacent RC buildings having same number of stories have been considered. For pounding case analysis there is no gap in between adjacent buildings and for no pounding case analysis there is sufficient distance between adjacent buildings. The model consists of adjacent buildings having 4 and 4 stories but unequal storey height. Both the buildings have same material & sectional properties. Fast non-linear time history analysis was performed by using El-centro earthquake data as ground motion. Adjacent buildings having different overall height were modelled in SAP 2000 v 15 using gap element for pounding case. Finally, analysis was done and inter-storey drift was compared. It was found that in higher building inter-storey drift is greater in no pounding case than in pounding case but in adjacent lower height building the result was reversed. Additionally, it was found that in general residential RC buildings maximum inter-storey drift occurs in 2nd floor.


2021 ◽  
Vol 11 (8) ◽  
pp. 3425
Author(s):  
Marco Zucca ◽  
Nicola Longarini ◽  
Marco Simoncelli ◽  
Aly Mousaad Aly

The paper presents a proposed framework to optimize the tuned mass damper (TMD) design, useful for seismic improvement of slender masonry structures. A historical masonry chimney located in northern Italy was considered to illustrate the proposed TMD design procedure and to evaluate the seismic performance of the system. The optimization process was subdivided into two fundamental phases. In the first phase, the main TMD parameters were defined starting from the dynamic behavior of the chimney by finite element modeling (FEM). A series of linear time-history analyses were carried out to point out the structural improvements in terms of top displacement, base shear, and bending moment. In the second phase, masonry's nonlinear behavior was considered, and a fiber model of the chimney was implemented. Pushover analyses were performed to obtain the capacity curve of the structure and to evaluate the performance of the TMD. The results of the linear and nonlinear analysis reveal the effectiveness of the proposed TMD design procedure for slender masonry structures.


Sign in / Sign up

Export Citation Format

Share Document