scholarly journals Seismic Vulnerability Analysis of Structure Subjected to Uneven Foundation Settlement

2019 ◽  
Vol 9 (17) ◽  
pp. 3507 ◽  
Author(s):  
Chao Bao ◽  
Fangze Xu ◽  
Gang Chen ◽  
Xiaotong Ma ◽  
Mingjie Mao ◽  
...  
Keyword(s):  
Seismic Response ◽  
Seismic Vulnerability ◽  
Steel Structure ◽  
Internal Force ◽  
Earthquake Damage ◽  
Foundation Settlement ◽  
Structural Failure ◽  
Loess Area ◽  
Collapsible Loess ◽  
The Relationship

Uneven foundation settlement is one of the common engineering problems in a collapsible loess area. In order to study the influence of uneven foundation settlement on the seismic performance of a structure, the incremental dynamic analysis (IDA) method is used to analyze the seismic vulnerability of the steel structure frame. The differences in the seismic response of the structure in relation to uneven foundation settlement are analyzed. The influences of uneven foundation settlement quantities and various areas of uneven settlement on the seismic response of the structure are discussed. On this basis, the relationship between ground motion intensity and structural failure probability is studied, by changing the magnitude of seismic acceleration peaks. Compared with the unsettled structure, the internal force redistribution of the structure caused by uneven foundation settlement is one of the causes of earthquake damage for some components. The uneven foundation settlement located at the corner of the plane of the structure is likely to cause more serious earthquake damage to the structure. Uneven settlement will cause an increase in storey drift. With the increase in settlement, the seismic damage of the superstructure will be aggravated.

scholarly journals Application of Controllable Splitting Grouting Technology in Loess Foundation Reinforcement

2021 ◽  
Vol 2101 (1) ◽  
pp. 012025
Author(s):  
Qingang Liu ◽  
Mingru Zhou ◽  
Lin Zhong ◽  
Shaofei Li ◽  
Yiming Chen
Keyword(s):  
Bearing Capacity ◽  
Foundation Settlement ◽  
Loess Area ◽  
Grouting Pressure ◽  
Collapsible Loess ◽  
Pressure Grouting ◽  
Jack Up ◽  
Heating Boiler ◽  
Large Heating

Abstract Taking the foundation settlement accident of a large heating boiler foundation in a city in collapsible loess area as an example, controllable splitting grouting can be achieved by controlling the grouting pressure, grouting pipe opening form, grouting volume and grouting method etc., so as to stabilize foundation settlement and improve foundation bearing capacity, for the boiler with large uneven settlement, for boilers with large uneven settlement, quicklime piles are used to jack up the foundation after splitting grouting to stabilize the foundation, the foundation is lifted with quicklime piles after splitting grouting to stabilize the foundation. The results show that the grouting amount of soil is within the design range, the grout splits in the soil several times to form a slurry vein, the settlement is stable after boiler reinforcement, the quicklime method can jack up the foundation and reduce the uneven settlement of the foundation, and the use of controllable splitting grouting can basically eliminate the slight collapsibility grade loess, which provides a new idea for solving the similar problem of uneven settlement of collapsible loess foundation buildings.

scholarly journals Optimization Analysis of Settlement Parameters for Postgrouting Piles in Loess Area of Shaanxi, China

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Zhijun Zhou ◽  
Shanshan Zhu ◽  
Xiang Kong ◽  
Jiangtao Lei ◽  
Tong Liu
Keyword(s):  
Compression Modulus ◽  
Summation Method ◽  
Cone Penetration ◽  
Optimization Analysis ◽  
Loess Area ◽  
Elastic Compression ◽  
Settlement Calculation ◽  
Side Resistance ◽  
Load Tests ◽  
The Relationship

The settlement calculation of postgrouting piles is complex and depends on the calculation method and parameters. Static load tests were conducted to compare the settlement characteristics of nongrouting and postgrouting piles, and three vital parameters in the layer-wise summation method were revised to predict the settlement of postgrouting piles. The elastic compression coefficient was deduced based on the Mindlin–Geddes method by considering the influence of the change in the pile side resistance distribution and end resistance ratio on the elastic compression after grouting. The relationship between the compression modulus and soil gravity stress and cone penetration resistance were established, respectively, using experimental data. The optimum value of the settlement empirical coefficient was determined using regional data. Finally, we used the postgrouting pile of the Wuqi–Dingbian expressway as a practical example. The results obtained from the layer-wise summation method after parametric optimization were close to the measured values. The results of this study provide reference data and guidance for the settlement calculation of postgrouting piles in this area.

scholarly journals Evaluation of p-delta effect in structural seismic response

2018 ◽  
Vol 162 ◽  
pp. 04019 ◽  
Author(s):  
Sardasht Sardar ◽  
Ako Hama
Keyword(s):  
Seismic Response ◽  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Time History ◽  
Steel Structure ◽  
Nonlinear Static Analysis ◽  
Structural Behavior ◽  
Finite Element Software ◽  
History Analysis ◽  
Nonlinear Static

Numerous recent studies have assessed the effect of P-Delta on the structures. This paper investigates the effect of P-Delta in seismic response of structures with different heights. For indicating the effect of P-Delta, nonlinear static analysis (pushover analysis) and nonlinear dynamic analysis (Time history analysis) were conducted by using finite element software. The results showing that the P-Delta has a significant impact on the structural behavior mainly on the peak amplitude of building when the height of the structures increased. In addition, comparison has been made between concrete and steel structure.

Preliminary Study of the Unsteady Response Spectrum Based on Time-Varying

2011 ◽  
Vol 346 ◽  
pp. 58-62
Author(s):  
Pei Qiang ◽  
Ping Guan ◽  
Jing Tian ◽  
Er Liang Chen
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Strong Motion ◽  
Maximum Response ◽  
Time Varying ◽  
Structural Failure ◽  
Time Duration ◽  
Structure Response ◽  
Preliminary Study ◽  
The Relationship

Engineering characteristics of ground motion can be defined by three factors that are respectively amplitude, frequency and duration. Any one of them in isolation are not fully made known for the ground notions affecting on the structure. Response spectrum theory is one of the principal methods in seismic analysis. The maximum response of structure under earthquake input is only varying with period in traditional response spectrum during the whole time duration. The relationship between the maximum response and duration can not be shown in the response spectrum of earthquake. The concept of unsteady response spectrum is based on moveable spectrum in this paper. Based on the conventional response spectrum, the factor of time is taken into account in unsteady response spectrum research. Then the response spectrum can be studied according to time varying. As examples for strong motion records obtained from WenChuan earthquake, two methods are proposed to research the effect of duration on response spectrum. The result of unsteady response spectrum can play an important role in the further study of the structural failure mechanism and cumulative damage under earthquake loadings.

Application of the Cyclic Strain Approach to the Fatigue Failure of Ship Structural Details

1987 ◽  
Vol 31 (03) ◽  
pp. 177-185
Author(s):  
Wolfgang Fricke ◽  
Hans Paetzold
Keyword(s):  
Fatigue Life ◽  
Plastic Region ◽  
Steel Structure ◽  
Cyclic Strain ◽  
Cyclic Stress ◽  
Damage Parameter ◽  
Elastic Plastic ◽  
Strain Behavior ◽  
Structural Details ◽  
The Relationship

The cyclic strain approach is useful for determining the fatigue life of notches strained in the elastic-plastic region. Examples are the flame-cut edges of cutouts in the ship steel structure. After the description of the cyclic stress-strain behavior of the usual mild steel, the individual elements of the approach are described: the probability distribution of load amplitudes, the relationship between load and local elastic-plastic strain, the relationship between the damage parameter and fatigue life, and finally the damage accumulation law. The approach is illustrated by two examples of longitudinal/transverse web intersections. In the first, the predicted life is confirmed by experimental results. The second example shows the approach for complicated load combinations. It is hoped that this paper will contribute to sound and crack-free ship structural details, particularly if unusual loads are applied to well-tried details or if simplified designs are introduced.

Numerical Modeling of RC Bridges for Seismic Risk Analysis

2016 ◽  
pp. 457-481
Author(s):  
Pedro Silva Delgado ◽  
António Arêde ◽  
Nelson Vila Pouca ◽  
Aníbal Costa
Keyword(s):  
Seismic Response ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Plastic Hinge ◽  
Probabilistic Approach ◽  
Damage Model ◽  
Experimental Tests ◽  
Concrete Bridges ◽  
Seismic Risk Analysis ◽  
Hinge Model

The main purpose of this chapter is to present numerical methodologies with different complexities in order to simulate the seismic response of bridges and then use the results for the safety assessment with one probabilistic approach. The numerical simulations are carried out using three different methodologies: (i) plastic hinge model, (ii) fiber model and (iii) damage model. Seismic response of bridges is based on a simplified plane model, with easy practical application and involving reduced calculation efforts while maintaining adequate accuracy. The evaluation of seismic vulnerability is carried out through the failure probability quantification involving a non-linear transformation of the seismic action in its structural effects. The applicability of the proposed methodologies is then illustrated in the seismic analysis of two reinforced concrete bridges, involving a series of experimental tests and numerical analysis, providing an excellent set of results for comparison and global calibration.

scholarly journals Irregularity Effects of Masonry Infills on Nonlinear Seismic Behaviour of RC Buildings

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Massimiliano Ferraioli ◽  
Angelo Lavino
Keyword(s):  
Seismic Response ◽  
Seismic Vulnerability ◽  
Eurocode 8 ◽  
Seismic Action ◽  
Rc Buildings ◽  
Infill Walls ◽  
Nonstructural Components ◽  
Action Effects ◽  
Masonry Infills ◽  
Shear Demand

Despite extensive research studies, the seismic response of infilled reinforced concrete buildings remains an open problem due to both the complexity of the interaction between the infill and the frame and the large number of parameters involved. Thus, guidelines for both modelling and analysis are still lacking and the infill walls are normally treated as nonstructural components in seismic codes. However, it may be not conservative to neglect the influence of infills. In fact, the infill masonry walls may significantly affect the stiffness, strength, and energy dissipation capacity of RC buildings, even when they are regularly distributed. Recognizing this influence and its importance on the vulnerability of infilled frames, Eurocode 8 requires amplifying seismic action effects due to infills. In this paper, the effectiveness of the Eurocode 8 design provisions for infill irregularity in plan and/or elevation was investigated. To this aim, different in-plan layouts of infill walls were selected as marginal cases for which Eurocode 8 does not require amplification of the action effects due to the presence of infills, or the additional measures to counteract these effects are not mandatory. The seismic vulnerability of the infilled RC buildings was evaluated using nonlinear static and nonlinear dynamic analyses. Both cracking and crushing of masonry and stiffness and strength degradation were considered in the analysis. The effect of the layout of the masonry infills on the seismic response in terms of resistance and displacement was evaluated. Results show that in one of the case studies here examined, it is not conservative to neglect the influence of infill panels. In fact, structural failure due to torsion and soft-storey effects may occur even in cases where Eurocode 8 does not require the amplification of the action effects. Finally, the total shear demand on columns may be underestimated, even in cases where the code provisions for infills irregularity are not mandatory, and the additional shear demand in the columns induced by the masonry infill is very low.

Sign in / Sign up

Export Citation Format

Share Document