scholarly journals Seismic Performance of Various Piles Considering Soil–Pile Interaction under Lateral Cycle Loads for Integral Abutment Jointless Bridges (IAJBs)

2020 ◽  
Vol 10 (10) ◽  
pp. 3406
Author(s):  
Fuyun Huang ◽  
Yulin Shan ◽  
Ahad Javanmardi ◽  
Xiaoye Luo ◽  
Baochun Chen

The flexural pile foundation is used in integral abutment jointless bridges (IAJBs) in practical engineering to effectively dissipate the horizontal reciprocating deformation induced by the ambient temperature or earthquake loadings. Various types of flexural piles including the H-shaped steel pile (HP), prestressed concrete pile (PC), prestressed high-strength concrete pile (PHC) as well as the reinforcement concrete pile (RC) have been implemented in IAJBs. However, there is a lack of comprehensive studies on the flexural deformation and seismic performances of these piles. In order to investigate and compare their mechanical behaviors and seismic performances, a low-cycle pseudo-static test on several different types of piles was carried out. The test results indicated that the plastic hinge location of piles moved to a deeper pile depth with the increase of reinforcement ratio, buried pile depth and prestressing level, which led to better pile–soil interaction. The crack resistance of a concrete pile was improved as the reinforcement ratio and prestressing level increased. Moreover, the rectangular pile had a better soil–pile interaction and energy dissipation capacity than the circular pile. The inflection point of the pile deformation shifted deeper as reinforcement ratio, buried pile depth and prestressing level increased, which improved the effective length and horizontal deformation capacity of piles. The H-shaped steel pile showed a better elastic-plastic deformation capacity, ductility and energy dissipation capacity as compared to the concrete pile. Moreover, the pile having a higher bearing ratio sustained larger lateral loads whereas the surrounding soil was subjected to higher loads. Finally, new seismic design criteria of three-stage seismic fortification and five damage level for the concrete piles of IAJBs were proposed.

2015 ◽  
Vol 9 (1) ◽  
pp. 295-307 ◽  
Author(s):  
Edelis del V. Marquez A. ◽  
William Lobo-Q ◽  
Juan C. Vielma

A comparative study has been done to analyze the behavior of regular steel building structures of 4, 6, 8 and 10 stories, located in seismic zone 5 and soil type S1. The structures were upgraded with different brace configurations according to current Venezuelan codes. A total number of 24 numerical models were analyzed considering non-linear static and incremental dynamic analysis (IDA). The buildings were initially designed as moment resisting frames, and upgraded with six different bracing configurations: concentric braces in “X” and inverted “V”; eccentric braces inverted "V" with horizontal links, inverted “Y” and “X” with vertical links. Short length links were used to ensure a shear failure. The used methodology is based on obtaining the capacity, IDA curves, and bilinear approximations of these curves that allow the determination of yield and ultimate capacity points, in order to estimate important parameters of seismic response: overstrength and ductility; and considering these areas under the curves to estimate elastic deformation energy, energy dissipated by hysteretic damping and equivalent damping. According to the results, the cases with no brace enhancement showed the lowest lateral strength and lateral stiffness and high deformation capacity. On the other hand, the concentric bracing cases, resulted with the highest stiffness and strength and the lowest deformation capacity, therefore they have low ductility and energy dissipation capacity under seismic loading. Structures with links showed intermediate stiffness and strengths, resulting in the best performance in terms of ductility and energy dissipation capacity. The present study provides a better understanding of the benefits of eccentrically braced systems.


2014 ◽  
Vol 684 ◽  
pp. 195-201
Author(s):  
Zhen Lei ◽  
Yong Wang ◽  
Jun Tong Qu

FRP strength technique can increase the lateral strength of masonry walls, but the effect of the presence of pre-damage in the walls before retrofitted has not been studied. In this study, the experimental results from two half-scale RC-brick masonry walls with opening retrofitted with BFRP composite strips are presented. One wall was initially damaged in shear loading up to its maximum strength, and then repaired with BFRP sheets; another one was directly strengthened with BFRP sheets in the same strengthening configuration. All the walls were subjected to cyclic in-plane shear loading up to failure. Compared to the strengthened walls, the repaired masonry wall has almost the same failure mode and FRP strain rule, and slightly lower lateral strength and deformation capacity as well as energy dissipation capacity.


Buildings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 16
Author(s):  
Guohua Sun ◽  
Fei Li ◽  
Qiyou Zhou

This study aimed to study the cyclic behavior of two-side-connected precast-reinforced concrete infill panel (RCIP). A total of four RCIP specimens with different slit types and height-to-span ratios modeled at a one-third scale were tested subjected to cyclic lateral loads. The failure mode, hysteretic behavior, lateral strength, stiffness degradation, ductility, and energy dissipation capacity of each RCIP specimen were determined and analyzed. The specimens experienced a similar damage process, which involved concrete cracking, steel rebar yielding, concrete crushing, and plastic hinge formation. All the specimens showed pinched hysteretic curves, resulting in a small energy dissipation capacity and a maximum equivalent viscous damping ratio lower than 0.2. The specimens with penetrated slits experienced ductile failure, in which flexural hinges developed at both slit wall ends. The application of penetrated slits decreased the initial stiffness and lateral load-bearing capacity of the RC panel but increased the deformation capacity, the average ultimate drift ratios ranged from 1.41% to 1.99%, and the lowest average ductility ratio reached 2.48. The specimens with high-strength concrete resulted in a small slip no more than 1 mm between the RC panel and steel beam, and the channel shear connectors ensured that the RC infill panel developed a reliable assembly with the surrounding steel components. However, specimens with concealed vertical slits (CVSs) and concealed hollow slits (CHSs) achieved significantly higher lateral stiffness and lateral strength values. Generally, the specimens exhibited two-stage mechanical features. The concrete in the CVSs and CHSs was crushed, and flexural plastic hinges developed at both ends of the slit walls during the second stage. With increasing concrete strength, the initial lateral stiffness and lateral strength values of the RCIP specimens increased. With an increasing height-to-span ratio, the lateral stiffness and strength of the RC panels with slits decreased, but the failure mode remained unchanged.


2022 ◽  
Vol 2148 (1) ◽  
pp. 012029
Author(s):  
Ying Luo ◽  
Fuyun Huang ◽  
Zhifu Chen ◽  
Xinghua Liu ◽  
Zhengfeng Liu ◽  
...  

Abstract In order to improve the ability of the reinforcement concrete (RC) pile foundation of integral abutment to absorb the horizontal reciprocating deformation under the action of temperature or earthquake, a pseudo-static low cycle test on interaction of pile-soil with high reinforcement ratio was carried out. The failure location, hysteresis curve, skeleton curve and horizontal deformation of three piles with different reinforcement ratios were compared. The test results show that, with the increase of the reinforcement ratio, the crack of the RC pile develops along the pile body to the depth, and the pile body failure area and the position where the maximum bending moment moves down, the crack resistance of the pile body is improved, and the effective interaction pile length increases; The test results also show that the hysteresis curve of the model pile becomes fuller with the increase of the reinforcement ratio, compared with the RCP-1 specimen with the lowest reinforcement ratio, the equivalent viscous damping ratio of the RCP-3 specimen is increased by 31.6%, and the energy dissipation capacity is improved. In addition, with the increase of the reinforcement ratio, the bearing capacity and deformation capacity of model piles are greatly improved. Compared with RCP-1 specimen, the ultimate bearing capacity of RCP-3 specimen increased by 150%, and the corresponding ultimate displacement increased by 153%. Increasing reinforcement ratio can significantly improve the mechanical properties and deformation capacity of RC pile.


1998 ◽  
Vol 1624 (1) ◽  
pp. 93-100 ◽  
Author(s):  
David H. Sanders ◽  
M. Saiid Saiidi ◽  
Troy Martin

Many bridges constructed in the 1960s in regions of high seismic risk have column–pier-cap connections with inadequate column bar development and no shear reinforcement in the joint region. The study described in this paper focuses on highway bridges built on Interstate 80 in the Reno, Nevada, area during the 1960s. Two 0.4-scale specimens representing the essential features of the column–pier-cap connections in these bridges were constructed and tested. One test showed that the asbuilt specimen had little energy dissipation capacity and failed at less than 1 percent drift. A second specimen was used to test a potential strengthening technique. The technique included increasing pier-cap depth, adding a concrete bolster to the joint, and placing a steel jacket around the column. After strengthening, a plastic hinge formed in the column, the joint damage was minimized, and the energy dissipation capacity increased by a factor of 5.


2020 ◽  
Vol 10 (4) ◽  
pp. 1358 ◽  
Author(s):  
Fuyun Huang ◽  
Yulin Shan ◽  
Guodong Chen ◽  
Youwei Lin ◽  
Habib Tabatabai ◽  
...  

Soil-abutment or soil-pile interactions under cyclic static loads have been widely studied in integral abutment jointless bridges (IAJBs). However, the IAJB has the combinational interaction of soil-abutment and soil-pile, and the soil-abutment-pile interaction is lack of comprehensively study. Therefore, a reciprocating low-cycle pseudo-static test was carried out under an cyclic horizontal displacement load (DL) to gain insight into the mechanical behavior of the soil-abutment-pile system. Test results indicate that the earth pressure of backfill behind abutment has the ratcheting effect, which induced a large earth pressure. The soil-abutment-pile system has a favorable energy dissipation capacity and seismic behavior with relatively large equivalent viscous damping. The accumulative horizontal deformation in pile will be occurred by the effect of abutment and unbalance soil pressure of backfill. The test shows that the maximum horizontal deformation of pile occurs in the pile depth of 1.0b~3.0b of pile body rather than at the pile head due to the accumulative deformation of pile, which is significantly different from those of previous test results of soil-pile interaction. The time-history curve for abutment is relatively symmetrical and its accumulative deformation is small. However, the time-history curve of pile is asymmetrical and its accumulative deformation is dramatically large. The traditional theory of deformation applies only to the calculation of noncumulative deformation of pile, and the influence of accumulative deformation should be considered in practical engineering. A significant difference of inclinations in the positive and negative directions increases when the displacement load is relatively large. The rotation of abutment when bridge expands is larger than that when bridge contracts due to earth pressure of backfill.


2020 ◽  
Vol 23 (12) ◽  
pp. 2514-2528
Author(s):  
Xiayun Song ◽  
Haiwang Li ◽  
Jie Zhang

As earthquakes tend to cause ultra-low cycle fatigue failure of spatial grid structures in composite members and joints, this study sets out to test six groups of specimen comprising steel pipes and bolt sphere joints and analyzes the influence of joints and loading systems on failure modes, hysteretic behavior, skeleton curves, stiffness degradation, energy dissipation capacity, and the formation and development of plastic hinges. Results showed that the instability of the specimen in compressive loading led to the occurrence of denting and the formation of plastic hinges. Cracks originated in dented area, and ultra-low cycle fatigue fractures occurred in a dozen cycles. Plastic hinge was located in the middle area of the pipe, and the energy dissipation capacity was limited owing to the confined plastic hinge length. As the joint bending stiffness increased, so did the length of the plastic hinge, the degree of the dent, and the cumulative damage. Early fractures and a reduction in total energy consumption also occurred. Furthermore, a function related to the cumulative damage and macroscopic deformation that can evaluate the damage of the members in spatial grid structures was also established.


Author(s):  
S. V. Khonsari ◽  
G. L. England ◽  
S. M. H. Parvinnia ◽  
E. Hajialiakbari-Fini

A new beam-to-column (horizontal brace-to-leg) and bracing-to-frame (diagonal brace-to-horizontal brace/leg) connection was developed. It is a comprehensive package in which the solution to all of the shortcomings and deficiencies of all conventional and/or commonly used connections is provided. The major deficiency of basically all the existing beam-to-column connections is their inability to deliver large rotations. In this devised connection, it has been solved by using a totally different geometry—a geometry which does not restrict the joint from deforming freely in a smooth, uniform and non-violent manner. Such mode of deformation, if delivered by a ductile material, should lead to a high energy dissipation capacity. Especially, if the ductility of the constituting material of the connection is not degraded as a result of fabrication operations, or if so, it is restored through practicing a suitable heat treatment process, e.g. annealing, the energy dissipation capacity should improve substantially. Moreover, in order to attract the damage and prevent it from spreading through the beam (bracing) and the column (leg), whose replacement is formidable, the connection should work in a ‘sacrificial’ capacity. This, together with making it ‘replaceable,’ will reduce the cost of aftermath repair substantially, while replacing the damaged beam or column, if possible, is very costly. In addition to its high rotational (bending) capacity, at least 6 times those of conventional joints (depending on the connection design), its ‘shear deformation capacity’ is quite considerable, absolutely incomparable with those of its conventional counterparts, which are virtually ‘nil.’ This connection is a ‘self-contained separate entity’ which comprises two parallel attachment plates between which two circular, or else, tubes are laid and fixed through welding, though alternatively the whole combination can be produced by extrusion. In the ‘original version’ of the connection, the two plates are laid in a parallel relation with the axis of bending, whereas in its ‘alternate version,’ they are laid in an orthogonal relation with the axis of bending. Tests carried out on specimens of the two distinct versions of the connection proved all its claimed characteristics, both in shear and bending. In particular, those carried out more recently, not reported in previous papers (OMAE’02-28264 & OMAE’03-37292), were quite revealing with regard to the ‘shear strength’ and the ‘shear deformation capacity’ of the original version (horizontally-laid-tube, HLT, version) of the connection—far beyond what was expected by the authors.


2014 ◽  
Vol 501-504 ◽  
pp. 969-976
Author(s):  
Long Min Jiang ◽  
Hong Jun Li ◽  
Lei Liu ◽  
Jin Dan Zhang

This paper described the characteristics of the existing methods of strengthening RC shear walls at home and abroad, and discussed the research and operation of strengthening RC shear walls using these methods. It focused on the performance characteristics of the reinforced shear walls structure such as the bearing capacity, the ductility, the deformation capacity and energy dissipation capacity. And the future research trend of the High Performance Ferrocement Laminate reinforcement method is presented.


2011 ◽  
Vol 368-373 ◽  
pp. 58-61 ◽  
Author(s):  
Bin Li ◽  
Zhong Zhou Han ◽  
Chun Yan Gao

Based on the 1.5MW cone cylinder wind turbine tower widely used at present, latticed concrete-filled steel tubular (CFST) tower with three limbs was designed. The stress mechanism and failure process, hysteretic properties, bearing capacity and energy dissipation capacity were studied by quasi-static test on the tower model. The results indicate that the hysteretic loops of the latticed CFST tower with three limbs present asymmetrical plump “spindle” and there is no obvious "pinch" phenomenon, which shows good seismic performance and energy dissipation capacity; and that owing to the latticed CFST tower with three limbs is asymmetric along the centroidal axis perpendicular to loading direction, plastic hinge finally appeared in the tower column foot which beared the largest force, the bottom web members were buckled and occur unstable failure. From the analysis it can be seen that the latticed CFST tower structure with three limbs has value of further research and promotion.


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