scholarly journals Fragility Analysis and Risk Assessment of Precast Concrete Frames with “Dry” Connections: A Comparative Study

2021 ◽  
Vol 1203 (3) ◽  
pp. 032045
Author(s):  
Chenhao Wu
Keyword(s):  
Energy Dissipation ◽  
Comparative Study ◽  
Seismic Risk ◽  
Social Impact ◽  
Precast Concrete ◽  
Time History ◽  
Fragility Functions ◽  
Concrete Frames ◽  
Energy Dissipation Devices

Abstract Precast concrete frames (PCFs) with "dry" connections and self-centering capacity have been proposed as a new kind of seismic protective structural system with characteristics of damage controllable mechanism, easy-assemblage and rapid repair speed. The damage mechanism of PCFs are concentrated at the panel zones under earthquake excitations, so as to avoid damage to beam and column components. Through reasonable design for the PCFs, not only the structural and life safeties can be guaranteed, but also the seismic loss and social impact can be minimized. This paper conducts a comparative study between PCFs with "dry" connections and conventional cast-in-situ concrete frame. A generalized beam-column connection analytical model is utilized to predict the seismic behaviour of PCFs with energy dissipation devices, with an emphasis on the opening behaviour at beam-column interfaces, the self-centering capacity provided by prestressed tendons and the hysteresis behaviour provided by energy dissipation devices. Prototype PCFs or cast in situ frame structures are designed to achieve similar deformation capacities in Chinese highly seismic fortification zone. Probabilistic seismic capacity analyses (PSCA) are conducted based on the results of probabilistic pushover analyses and Latin Hypercube Sampling. Incremental dynamic analysis method combined with nonlinear time history analyses are utilized to conduct probabilistic seismic demand analyses (PSDA). Fragility functions of different structural systems are derived based on the convolution of PSCA and PSDA. Finally, the seismic risk is evaluated based on the fragility functions and the developed Chinese seismic code compliant hazard functions. The results indicate that PCFs with energy dissipation devices can have lower seismic risk than conventional cast-in-site frames.

Study on Time History Method of Structure with Energy-Dissipation Devices Based on Complex Mode

2011 ◽  
Vol 94-96 ◽  
pp. 1192-1195
Author(s):  
Zhi Qiang Bai ◽  
Wen Feng Liu
Keyword(s):  
Differential Equation ◽  
Energy Dissipation ◽  
Time History ◽  
Equation Of Motion ◽  
Complex Mode ◽  
Dissipation Structure ◽  
Energy Dissipation Devices

Differential equation of motion of energy-dissipation structure is established in the paper. In order to decouple the equation ,the equation is be reduced based on complex mode theory.Take a 10-storey shearing frame for an example ,selecting elcentro and taft wave as seismic motions ,structural roof displacements and relative storey displacements are be calculated and the effect of energy-dissipation dampers is evaluated.

Seismic design of hybrid unbonded post-tensioned precast concrete joints based on bearing capacity and energy dissipation capacity

2020 ◽  
pp. 136943322098273
Author(s):  
Baoxi Song ◽  
Weizhi Xu ◽  
Dongsheng Du ◽  
Shuguang Wang ◽  
Weiwei Li ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Design Method ◽  
Precast Concrete ◽  
Residual Deformation ◽  
Time History ◽  
Frame Structure ◽  
Energy Dissipation Capacity ◽  
Concrete Joints ◽  
Post Tensioned

This paper provides a practical design method for hybrid unbonded post-tensioned precast concrete joints. Such joints featured with self-centering capacities have been widely favored in recent years. However, the absence of design methods hinders their further promotion. To solve the issue, two methods for calculating mechanical behavior of the joints were first studied: characteristic points method and iterative method. The effectiveness of the methods was verified by the existing test results. On this basis, a joint design method considering both yield bearing capacity and energy dissipation capacity was proposed. Moreover, to facilitate design, some factors affecting the bearing capacity were discussed. A five-story frame structure was designed by the proposed design method, and the influence of two design factors on structural response was analyzed by utilizing nonlinear time-history method. The analysis results show that: with the increase of energy dissipation factor αs, the post-earthquake residual deformation of the structure tends to increase linearly, while the accumulated damage of the structure will decrease continuously; both overdesign and underdesign of bearing capacity of the joint are unfavorable; and near-field earthquake may cause irreparable damage to structural columns, making the residual deformation of structures contrary to the self-centering capacity of joints, which shall be considered during engineering design.

Viscous Dampers Utilized at an Operating Electronic Facility for Reducing Seismic Risk

2014 ◽  
Vol 1021 ◽  
pp. 128-139
Author(s):  
Heng Sheng Chang ◽  
Ji Ping Ge
Keyword(s):  
Energy Dissipation ◽  
Seismic Activity ◽  
Seismic Risk ◽  
Semiconductor Manufacturing ◽  
Damping Ratio ◽  
Viscous Damper ◽  
Fundamental Vibration ◽  
Passive Energy Dissipation ◽  
Energy Dissipation Devices

Using supplemental energy dissipation devices into the structure to increase the damping ratio for reducing the responses of seismic activity has become more and more popular. This paper presents a case study of seismic retrofit strategy, utilizing a type of passive energy dissipation device, namely, the viscous damper, in order to make an ongoing chips produced facility resistant to seismic activity. The building in question was a chips produced facility belonging to a semiconductor manufacturing company. This was a double FAB where the structure system was divided into an island building and an RC shell. The retrofit involved installing 44 non-linear dampers between the island building and the RC shell. This was due to the significant differences in the fundamental vibration periods. This paper will present the rationale of making a decision on the parameters of the dampers to give the optimum retrofit strategy.

scholarly journals Estimation of Seismic Economic Loss and Downtime of Precast Concrete Frames with “Dry” Connections

2021 ◽  
Vol 1203 (3) ◽  
pp. 032046
Author(s):  
Chenhao Wu
Keyword(s):  
Precast Concrete ◽  
Economic Loss ◽  
Structural Components ◽  
Concrete Frames ◽  
Rapid Repair ◽  
Seismic Loss ◽  
Earthquake Loss ◽  
The City ◽  
Hazard Levels

Abstract The seismic loss of buildings comes not only from the damaged structural components. Much more loss may be induced by non-structural components, the demolition loss and social impacts associated with excessive downtime. One of the main characteristics of a resilient city is that the buildings in the city should be able to recover to their pre-earthquake functionalities with minimized economic loss and downtime. For this purpose, a comparative study regarding seismic economic loss and downtime is conducted between the conventional cast-in-situ reinforced concrete frames (RCFs) and precast concrete frames (PCFs) with "dry" connections. The results show that the PCFs with prestressed tendons (PTs) can effectively reduce demolition loss given their extraordinary self-centering capacity provided by PTs. By adding web friction devices at the beam ends, the economic loss of structural components and drift-sensitive non-structural components can be effectively reduced. The downtime of PCFs is reduced at given hazard levels compared with RCF given their rapid repair speed and easy assemblage. In view of the rapid post-earthquake repair and lower earthquake loss, the PCFs are worth further investigation and application to develop resilient cities.

scholarly journals Seismic Risk Assessment of a Novel Self-Centering Precast Concrete Frame under Near-Fault Ground Motions

2020 ◽  
Vol 10 (18) ◽  
pp. 6510
Author(s):  
Fangfang Geng ◽  
Youliang Ding ◽  
Honglei Wu ◽  
Kang Yang
Keyword(s):  
Risk Assessment ◽  
Dynamic Analysis ◽  
Seismic Performance ◽  
Seismic Risk ◽  
Precast Concrete ◽  
Time History ◽  
Seismic Intensity ◽  
The Novel ◽  
Concrete Frame ◽  
Near Fault

The damage to structures caused by the velocity pulse effect of near-fault earthquake waves cannot be ignored, yet there are few studies on the risk assessment of seismic performance for precast concrete frame under near-fault earthquake waves. A novel self-centering precast concrete (SCPC) frame with hysteretic dampers is proposed to obtain great self-recovering and energy consumption characteristics. To accurately assess the seismic behaviors of the novel SCPC frame under the near-fault earthquake waves, a prototype structure is modelled and elastoplastic dynamic analysis is conducted at the design basis earthquake (DBE) and the maximum considered earthquake (MCE) seismic levels. Incremental dynamic analysis and the vulnerability analysis are performed. Annual and 50-year exceeding probabilities of the novel SCPC frame are calculated afterwards. In addition, the reinforced concrete (RC)frame and the traditional SCPC frame are also modelled, whose section sizes, reinforcements arrangement and seismic intensity are consistent with the novel SCPC frame. The dynamic time-history analysis at the two seismic levels are also carried out for two types of frames. The analysis results demonstrate that the novel SCPC frame has great seismic performance and low seismic risk possibility under the near-fault earthquakes loading.

scholarly journals Influence of Modelling Assumptions on the Seismic Risk of Industrial Precast Concrete Structures

2021 ◽  
Vol 7 ◽  
Author(s):  
Michele Egidio Bressanelli ◽  
Davide Bellotti ◽  
Andrea Belleri ◽  
Francesco Cavalieri ◽  
Paolo Riva ◽  
...  
Keyword(s):  
Seismic Risk ◽  
Precast Concrete ◽  
Time History ◽  
Experimental Tests ◽  
3D Models ◽  
Industrial Building ◽  
Linear Connections ◽  
Non Linear ◽  
Modelling Strategies ◽  
Modelling Assumptions

This research evaluates the influence of different modelling assumptions on the global and local seismic risk assessment of code-conforming precast reinforced concrete buildings, specifically single-story industrial buildings. In particular the modelling of the system mass, the overhead crane, the beam-to-column and roof-to-beam connections and the cladding system are investigated. For this purpose, a case study resembling a new industrial building designed in accordance with the current Italian building code was selected. Typical dowel beam-to-column connections were considered and the influence of various modelling strategies investigated: perfect hinges, linear elastic connections and non-linear connections with a degrading hysteretic force-displacement model which was calibrated from available data on experimental tests. Three different types of roof-to-beam connections were investigated removing the assumption of rigid diaphragm, namely hot-rolled, cold-formed and socket welded connections. Initially, simplified planar models of single frames were considered to evaluate the influence of the different modelling strategies, then 3D models of the entire building were analyzed. Multiple-stripe non-linear dynamic time history analyses allowed to evaluate displacements, drifts, deformations and ultimate curvatures of the main elements and connections for various intensity measure levels. The seismic risk was assessed in terms of failure rate considering the collapse of both the columns and of the connections. The results show that the beam-to-column connections fail right after reaching yielding due to their low displacement ductility, leading to the loss of support of the beam and therefore increasing the collapse rate of the investigated structural typology.

scholarly journals Parametric Study on Self-centering Precast Concrete Frames with Hysteretic Dampers

2021 ◽  
Author(s):  
Yadong Li ◽  
Fangfang Geng ◽  
Youliang Ding ◽  
Libin Wang
Keyword(s):  
Energy Dissipation ◽  
Rational Design ◽  
Modular Design ◽  
Precast Concrete ◽  
Time History ◽  
Bending Moment ◽  
Frame Structure ◽  
Concrete Frame ◽  
Energy Dissipation Capacity ◽  
Hysteretic Dampers

The self-centering precast concrete frame structure combines the advantages of industrialization and low earthquake damage, and its energy dissipation capacity and seismic performance have always been the focus of research. This paper proposed a kind of self-centering precast concrete frame with hysteretic dampers (SCPCHD). Its modular design makes the energy dissipation device and components easy to repair and replace. In order to obtain the optimal design, the finite element models of SCPCHD frames with different layout types of post-tensioned (PT) tendons and different shapes of hysteretic dampers are established, and the elastoplastic dynamic time-history analyses are carried out. The results show that the layout types and vertical margin of PT tendons have little effect on the displacement response of the frame structure. Compared to linear PT tendons, polygonal PT tendons can better bear the bending moment of the beam and reduce the stress of longitudinal reinforcements in the beam. The reduce effect of shortening the vertical margin on the tensile damage of beam concrete is obvious in the frame with polygonal PT tendons, but not obvious in the frame with linear PT tendons. Rational design of the prestressing force also plays a crucial role in the energy dissipation capacity of SCPCHD frames.

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