Study on reinforcement effect of H type assembled anchoring joint in portal frame

2021 ◽  
pp. 136943322098273
Author(s):  
Sun Yu-qing ◽  
Liu Xinjie ◽  
Cui Weilong ◽  
Zhang Shilian ◽  
Wu Qingbo ◽  
...  

With the development of society, portal frame has been increasingly used in industrial buildings because of light weight, high degree of industrialization, and high economic efficiency. Some existing portal frames need to be reinforced and improved due to the expansion of production and the functional change. As a safe, reliable, and convenient reinforcement method, the external prestressing reinforcement technology is often used to reinforce the portal frame. In this paper, a new type of assembled anchoring joint was designed to connect the steel strand to the steel beam of a portal frame without damaging the original structure. The static loading test was performed by adjusting length of the strut. And the changes of strain and mid-span deflection were investigated. The Midas Gen FEM simulation was used to investigate stress characteristics of the reinforced portal frame, including strain, bending moment, shear force, etc. The experimental results and simulation results were compared to verify effectiveness of the designed joint. The results indicated the new prestressed anchoring joints had the advantages of simple structure, effectiveness, and force transfer path of the joints was clear. Therefore, the new prestressed anchoring joint can be applied to the external prestressing reinforcement of the portal frame.

Author(s):  
Petr Bílý ◽  
Alena Kohoutková ◽  
Petr Jedlinský

Author(s):  
Bengt Fellenius

On April 4, 2018, 209 days after driving, a static loading test was performed on a 50 m long, strain-gage instrumented, square 275-mm diameter, precast, shaft-bearing (“floating”) pile in Göteborg, Sweden. The soil profile consisted of a 90 m thick, soft, postglacial, marine clay. The groundwater table was at about 1.0 m depth. The undrained shear strength was about 20 kPa at 10 m depth and increased linearly to about 80 kPa at 55m depth. The load-distribution at the peak load correlated to an average effective stress beta-coefficient of 0.19 along the pile or, alternatively, a unit shaft shear resistance of 15 kPa at 10 m depth increasing to about 65 kPa at 50 m depth, indicating an α-coefficient of about 0.80. Prior to the test, geotechnical engineers around the world were invited to predict the load-movement curve to be established in the test—22 predictions from 10 countries were received. The predictions of pile stiffness, and pile head displacement showed considerable scatter, however. Predicted peak loads ranged from 65% to 200% of the actual 1,800-kN peak-load, and 35% to 300% of the load at 22-mm movement.


2017 ◽  
Vol 83 (852) ◽  
pp. 17-00050-17-00050 ◽  
Author(s):  
Tsuyoshi FUKASAWA ◽  
Shigeki OKAMURA ◽  
Tomohiko YAMAMOTO ◽  
Nobuchika KAWASAKI ◽  
Satoru INABA ◽  
...  

2013 ◽  
Vol 405-408 ◽  
pp. 1616-1622
Author(s):  
Guo Hui Cao ◽  
Jia Xing Hu ◽  
Kai Zhang ◽  
Min He

In order to research on mechanical properties of flexible suspension bridges, a geometric nonlinear analysis method was used to simulate on the experimental results, and carried on static loading test finally. In the loading test process, the deformations were measured in critical section of the suspension bridge, and displacement values of measured are compared with simulation values of the finite element simulation. Meanwhile the deformations of the main cable sag are observed under classification loading, the results show that the main cable sag increment is basically linear relationship with the increment of mid-span loading and tension from 3L/8 and 5L/8 to L/2 section, the main cable that increasing unit sag required mid-span loads and tension are gradually reduce in near L/4 and 3L/4 sections and gradually increase in near L/8 and 7L/8 sections and almost equal in near L/2, 3L/8 and 5L/8 sections. From the experimental results, the flexible suspension bridge possess good mechanical properties.


2021 ◽  
Vol 11 (6) ◽  
pp. 2553
Author(s):  
Sang-Hyun Kim ◽  
Jong-Sup Park ◽  
Woo-Tai Jung ◽  
Jae-Yoon Kang

Various methods for strengthening existing structures have been developed owing to the increase in human and property damages caused by the deterioration of structures. Among the various reinforcing methods, the external prestressing method increases the usability and safety of a structure by directly applying tension to the weak tensile area that suffers the greatest deflection during the structure usage. The external prestressing method is advantageous in reducing cracks caused by the introduced tension and restoration of the deflection. Since the strengthening method is applied to deterioration bridges, the strengthening effect is affected by the condition of the existing structure. However, studies on the strengthening effect according to the degree of deterioration are insufficient. Therefore, the behavior according to the strengthening status was analyzed, and the strengthening effect was identified in this study by simulating the deteriorated bridge, reducing the compressive strength and reinforcement quantity, and conducting a four-point loading test. As a result of the experiment, a reinforcement effect of 215% crack load, 161% yield load, and the difference in behavior according to the reinforcement parameters were confirmed.


Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 12
Author(s):  
Łukasz Święch ◽  
Radosław Kołodziejczyk ◽  
Natalia Stącel

The work concerns the experimental analysis of the process of destruction of sandwich structures as a result of circumferential shearing. The aim of the research was to determine the differences that occur in the destruction mechanism of such structures depending on the thickness and material of the core used. Specimens with a Rohacell foam core and a honeycomb core were made for the purposes of the research. The specimen destruction process was carried out in a static loading test with the use of a system introducing circumferential shear stress. The analysis of the tests results was made based on the load-displacement curves, the maximum load, and the energy absorbed by individual specimens. The tests indicated significant differences in the destruction mechanism of specimens with varied core material. The specimen with the honeycomb core was characterized by greater stiffness, which caused the damage to occur locally in the area subjected to the pressure of the punch. In specimens with the foam core, due to the lower stiffness of that core, the skins of the structure were bent, which additionally transfers compressive and tensile loads. This led to a higher maximum force that the specimens obtained at the time of destruction and greater energy absorption.


Author(s):  
Bengt Fellenius

Results of a static loading test were used together with soil exploration records in a survey comprising analysis of the test records and estimating settlement of piled foundation to support a pipe rack. The test pile was a strain-gage instrumented, 400-mm diameter, precast, prestressed concrete pile driven into a clay and silt deposit to 25 m embedment. Two main issues were expected to be addressed by the survey participants: First, realization that the strain records were affected by presence of residual force in the pile and, second, calculation of the settlement of the piled foundation expected from the foundation load. A total of 52 submissions were received from 20 different countries. Only 12 of the submissions realized the presence of residual force. Most submissions reported a calculated settlement of the piled foundations ranging from 10 mm through 50 mm; however, 11 reported values between 60 and 200 mm. Surprisingly, only 20 submissions reported ground surface settlement close to the 200-mm value resulting from text-book analysis based on the available information. The subsequent construction of the piled foundations coincided with placing a fill across the site and lowering of the groundwater table, thus, causing a general subsidence.


2010 ◽  
Vol 163-167 ◽  
pp. 2852-2856
Author(s):  
Chang Wu ◽  
Xiu Li Wang

In this study a kind of buckling-restrained braces (BRBs) as energy dissipation dampers is attempted for seismic performance of large span double-layer reticulated shell and the effectiveness of BRBs to protect structures against strong earthquakes is numerically studied. The hysteretic curve of such members is obtained through the simulation of the cyclic-loading test, and the equations of motion of the system under earthquake excitations are established. BRBs are then placed at certain locations on the example reticulated shell to replace some normal members, and the damping effect of the two installation schemes of BRBs is investigated by non-linear time-history analyses under various ground motions representing major earthquake events. Compared with the seismic behavior of the original structure without BRBs, satisfactory seismic performance is seen in the upgraded models, which clarifies the BRBs can reduce the vibration response of spatial reticulated structure effectively and the new system has wide space to develop double layer reticulated shell.


Author(s):  
Askar Zh. Zhussupbekov ◽  
Yoshinori Iwasaki ◽  
Abdulla R. Omarov

At the present time, in Astana city is going on works by construction public transport system LRT (Light Railway Transport). LRT is an overhead road with two railway lines. The first stage of construction is including construction of overhead road (bridge) with 22,4 km length and 18 stations. The foundation of bridge is the bored piles with cross-section 1.0HL5 m and length 8-КЗ 5 m. In these conditions, very important to control integrity of concrete body of each bored piles. For checking integrity- applying two methods - Low Strain Method and Cross-Hole Sonic Logging. The aim of this paper is to discuss the advantages and disadvantages of each method using the examples of a real application. The article presents loading tests of large diameter and deep boring piles on the construction site in new capital city of the Republic of Kazakhstan. Finally, some recommendations for testmg methods suitable for problematical ground conditions of Kazakhstan are introduced. Traditionally, pile load tests in Kazakhstan are carried out using static loading test methods. Static pile loading test is the most reliable method to obtain the load-settlement relation of piles. Results of static pile tests using the static compression loading test (by ASTM). static loading test (by GOST) and bi-direction static loading test (by ASTM) methods are presented in this paper. Experienced bored piles with length of 31.5 m. diameter 1000 mm. Hereafter the results of underground testmg by the piles with the methods of vertical static tests of SLT. BDSLT and SCLT are presented, which had been made on Expo 2017 projects, buildings of Pavilion m Astana. Kazakhstan.


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