Force Response Spectrum Research Articles

REDESAIN BANGUNAN TAHAN GEMPA HOTEL 6 LANTAI DI WILAYAH YOGYAKARTA BERDASARKAN SNI GEMPA 1726:2019

The Province of the Special Region of Yogyakarta is one of the parts affected by the natural earthquake due to being passed by three tectonic plate meeting points, namely the Indo-Australian Plate, the Eurasian Plate, and the Pacific Plate. As a result, the surrounding high-rise buildings were damaged. The 6-storey hotel building in Yogyakarta was opened in 2019 referring to the earthquake SNI. The plan for this building will be designed based on SNI 1726:2019 concerning Procedures for Planning Earthquake Resistance for Building and Non-Building Structures and SNI 2847:2019 Requirements for Structural Concrete for Buildings and Non-Building Structures using Etabs v.20.0 software. After the redesign process was carried out, it resulted in changes to the spectrum response graph in SNI 1726: 2019 article 6.4, the seismic force response spectrum controlled by an equivalent static earthquake in SNI 1726: 2019 article 7.9.1 and article 7.9.2.5.2 resulted in a scale factor of 2.182 m/ s2 and do not experience deviations between levels. There are changes in the dimensions of the beams, changes in the longitudinal and transverse reinforcement in the beams and columns, and there are changes in the spacing of the reinforcement in the beams, columns, and floor slabs.

Simplified design method of pounding-unseating-prevention device for LRB isolated continuous girder bridge

Although cable restrainer and pull rod restrainer can reduce the seismic response of bridge structures to a certain extent, they cannot have good restrain and anti-pounding functions simultaneously. This paper proposes a simplified design method of a pounding-unseating-prevention device composed of rubber buffer block and steel block. The iterative design method of the device based on the pounding force response spectrum is studied according to the two-dimensional simplified analysis model of the isolated continuous girder bridge. The simplified design method considers the influence of factors, such as the difference in the dynamic characteristics of adjacent structures, ground motion characteristics and site conditions, through the pounding force response spectrum. To evaluate the effectiveness of the design method, nonlinear time history analysis is conducted on the lead rubber bearing (LRB) isolated continuous girder bridge with pounding-unseating-prevention device. The effectiveness of the device and the rationality of the design method are verified by comparing the relative displacement of the pier-girder and the maximum pounding force. Results show that the device designed using this simplified design method can reduce the pounding response of the structure and avoid the pounding of adjacent girders and unseating effectively.

Earthquake Response Spectra Analysis of Bridges considering Pounding at Bilateral Beam Ends Based on an Improved Precise Pounding Algorithm

Asynchronous vibration was generated between the main bridge and approach spans or abutments due to differences in stiffness and mass during an earthquake, thus further leading to pounding at the bilateral beam ends. By taking a T-shaped rigid frame bridge as an example, the bilateral pounding model was abstracted, and the earthquake response spectra considering pounding at the bilateral beam ends were studied, including the maximum displacement spectrum, the acceleration dynamic coefficient spectrum, the pounding force response spectrum, and the response spectrum for the number of pounding events. An improved precise pounding algorithm was proposed to solve the dynamic equation of the bilateral pounding model. This algorithm is based on the precise integration method for solving the second-order dynamic differential equation and reduces the order thereof by introducing a new velocity vector and uses the series method to find the nonhomogeneous term. The system matrix is simpler, and the inversion of the system matrix can be avoided. On this basis, a multipoint earthquake-induced pounding response spectrum program was developed. A total of 18 seismic waves from Class II sites were selected, and the response spectra of 18 waves were analyzed using this new program. Furthermore, the effects of structural stiffness, mass, stiffness of contact element, pounding recovery coefficient, and peak ground acceleration (PGA) on the earthquake response spectrum were studied. Through the analysis of earthquake response spectra and a parametric study, the phenomenon of earthquake-induced pounding of bridges was clarified to the benefit of the analysis and engineering control of earthquake-induced pounding of bridges.

Pounding force response spectrum for near-field and far-field earthquakes

Inadequate separation distance between neighboring buildings with out-of-phase response would increase the probability of pounding during an earthquake and may cause severe damages to the structures. A rational estimation of the maximum impact force would help us to control the extent of damages in different structures. As a practical tool, the pounding force response spectrum, which shows the value of maximum impact force as a function of the structural vibration periods, is considered in this paper. It is well-known that strong ground motion in the near-field area has different characteristics from far-field ones. In this paper, pounding force response spectra for elastic structures subjected to near-field and far-field ground motions are presented. Both of the adjacent buildings were modeled simply as Single-Degree-Of-Freedom (SDOF) systems and pounding effect has been simulated by applying the nonlinear viscoelastic model. In the analysis, the effect of different parameters, such as mass, damping ratio has been studied. The effects of gap distance on maximum pounding force due to near- and far-field earthquake ground motions were investigated comprehensively. As a result, the characteristics of earthquake ground motions along with the properties of structures should be considered in gap distance controlling between adjacent buildings.

Pounding force response spectrum under earthquake excitation

Earthquake-induced pounding between inadequately separated structures may cause considerable damage or even lead to a structure’s total collapse. The assessment of the damage magnitude as well as the design of some pounding mitigation method requires the knowledge of the maximum impact force value expected during the time of earthquake. The aim of the present paper is to propose the idea of impact force response spectrum for two adjacent structures, which shows the plot of the peak value of pounding force as a function of the natural structural vibration periods. In the analysis, both structures have been modelled by single-degree-of-freedom systems and pounding has been simulated by the non-linear viscoelastic model. The analysis has been conducted for elastic and inelastic (elastoplastic) structures under different ground motions. The examples of response spectra show that the selection of the structural parameters, such as the gap size between structures, their natural vibration periods, damping, mass and ductility as well as the time lag of input ground motion records, might have a substantial influence on the peak pounding force value. The results of the study indicate that impact force response spectra might serve as a very useful tool for the design purposes of closely-spaced structures on seismic areas.

Impact Force Spectrum for Damage Assessment of Earthquake-Induced Structural Pounding

Past earthquakes indicate that pounding between inadequately separated structures may cause considerable damage or even lead to collapse of colliding structures. Intensive study has been recently carried out on mitigation of pounding hazards. The assessment of damage due to structural pounding, or its prediction under a particular ground motion, requires the knowledge of the maximum impact force value expected during the time of earthquake. The aim of the present paper is to consider the concept of impact force response spectrum for two closely-spaced structures, which shows the plot of the peak value of pounding force as a function of the natural structural vibration period. The spectrum can be used as a practical tool to assess the magnitude of the expected pounding-induced damage and, if necessary, to apply some damage reduction techniques. In the analysis, both interacting structures have been modelled by single-degree-of-freedom systems and pounding has been simulated by the non-linear viscoelastic model, which accounts for the energy dissipation during impact. The examples of response spectra show that the appropriate selection of the separation gap between structures as well as the dynamic structural parameters, such as the natural vibration period, mass and damping, might have a significant influence on the intensity of damage due to earthquake-induced pounding.