A Residential Building Crack Test and Construction Safety Assessment

2012 ◽  
Vol 188 ◽  
pp. 119-122
Author(s):  
Ju Gang Luo ◽  
Jin Yang Zhang ◽  
Qing Song Zhang

A residential building, a brick/concrete structure built up in 1990s was used for many years. Since a deep foundation pit construction was being done in the north, the residents were worrying about the cracks in the building and its safety. Therefore, the following works were done such as the spot checks of the building engineering quality were done; the test and analysis were carried out over the cracks development after the foundation pit was backfilled, the influence assessment of the foundation construction under the mutual effects of pilings and anchor rods over the residential building structure was also conducted; finally the recheck calculation and safety evaluation were made over the building structure. The result shows that the foundation digging leads to new cracks on the nearby residential building but does not endanger its structural safety; after the foundation was backfilled, the hidden danger on the building’s northern side slop was eliminated and the structure cracks tend to be stable; the complete engineering structure is safe and in conformity with the requirements of safety and anti-vibration during the construction period, however, the multiple-pore slabs’ piecing affects the structural integrity and vibration proof performance.

2015 ◽  
Vol 744-746 ◽  
pp. 579-583
Author(s):  
Hui Min Wang ◽  
Zhen Jian Ji ◽  
Liang Cao ◽  
Ji Yao ◽  
Shan Guang Qian

Deep Pit is the main content of modern urban geotechnical engineering. In this paper, based on a deep foundation pit engineering as an example, based on the nonlinear finite element theory, conduct a numerical simulation research for foundation pit excavation process. Obtained the distribution law of pit deformation, stress distribution and the supporting structure of the internal forces, under the various processes. These provide a theoretical basis for safety evaluation of foundation pit engineering.


Author(s):  
Morten Lovstad ◽  
Tor G. Syvertsen

Abstract Huge steel or reinforced concrete structures in deep waters support the installations for oil and gas production in the North Sea. Steady operations in a hostile environment require that structural safety and integrity is maintained. For rapid evaluation and assessment of structural integrity in case of modifications or urgency situations, Structural Integrity Systems are established, comprising computational models and structural analysis programs. A major problem for structural assessment at short notice is to keep the analysis models updated and consistent with the actual state of the physical structure and the loadings. This paper proposes a layered approach for model integration, which enable maintenance of the models at a high level, from which detailed analysis models are derived in a consistent manner.


2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Chunlei Feng ◽  
Dingli Zhang ◽  
Hualao Wang ◽  
Xuan Zhang

Based on the sand and pebble stratum in the Beijing area, this paper studies the interaction between deep-foundation-pit excavation for subway stations and surrounding buildings using an orthogonal test. Moreover, it considers the relative position relationship between buildings and how the foundation pit is set up as well as different design schemes for foundation pits and the surrounding buildings. Results show that the horizontal distance s between the building and foundation pit and stiffness of the building itself have a clear impact on the differential settlement δij and relative deflection Δ, and the degree of deformation of the building near the corner of the foundation pit is complex. Simultaneously, based on numerical simulation results, the deformation characteristics and degree of deformation of the building under different relative position relationships with the foundation pit are analyzed. Finally, by establishing a relationship among the comprehensive deformation index Dj, surrounding environmental safety evaluation index Sj, and scheme safety grade Lj, a multiangle safety evaluation method for buildings affected by foundation-pit construction is formed, which can provide a reference for the research and design of similar projects.


2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Zhouqiang Li

Taking a super large deep foundation pit project as an example, the horizontal displacement of crown beam and driveway, surface settlement, axial force of anchor cable, and underground water level in the construction process of the foundation pit are dynamically monitored and analyzed. The excavation deformation rule of the deep foundation pit and the influence of excavation on surrounding buildings are analyzed. The results show that, with the excavation of the foundation pit, the crown beam and driveway of the foundation pit incline towards the direction of the pit and eventually tend to be stable. The variation of axial force of the prestressed anchor cable in the first layer of the foundation pit is basically consistent with the variation of horizontal displacement time history. The variation trend of the groundwater level at each side of the foundation pit is different but tends to be stable in a short time. In the whole monitoring period, the cumulative settlement value of each area of the foundation pit is within the controllable range, but the surface settlement of the north side of the foundation pit and a surrounding building has not reached stability, so it is suggested to extend the monitoring time of settlement in the relevant area.


2013 ◽  
Vol 438-439 ◽  
pp. 1423-1426
Author(s):  
Xin Zhong Zhang ◽  
Yong Jun Cheng ◽  
Ke Dong Tang

This paper introduces the "Levels of anchor cable +Bored piles +Net shotcrete combined support plans application in deep foundation pit engineering at Zhengzhou north freight marshalling station. Construction practice and monitoring data show that the engineering supporting design and construction have got an ideal effect, to ensure the safety of the north Ring Bridge and the railway line. It has a certain guiding significance to similar municipal engineering.


2014 ◽  
Vol 1021 ◽  
pp. 96-99
Author(s):  
Jia Yang Wang ◽  
Xiao Qiang Wang

According to the building settlement monitoring around the base pit, research the deep base pit excavation impacting on the surrounding buildings. Take Hefei subway station base pit project as example, by way of an adjacent residential building whole process of excavation monitoring, research the impact of deep excavation on the surrounding buildings. Timely feedback to the construction unit, to ensure the smooth construction of pit, and provides a reference to design and construction of deep foundation pit.


2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Wei Gang ◽  
Zhou Xin-Xin ◽  
Xu Yin-Feng ◽  
Zhang Li ◽  
Zhang Xin-Hai

A deep foundation pit in a station of the Hangzhou subway is adjacent to new high-rise residential buildings on the north side and to the Evergrande foundation pit being excavated on the south side. This work considers the excavation of the foundation pit in the subway station as the research subject, focuses on the difference of the deformation and Earth pressure between the north side and the south side of the foundation pit under these special working conditions through the analysis of the measured data, and compares it with an ordinary foundation pit. Analyzing the measured data reveals that the horizontal displacement of the retaining wall and the ground settlement are far larger on the north side than on the south side, and both often exceed the deformation alarm value; the deformation of the ordinary foundation pit is between the deformation of the overloaded (north) side and that of the unloaded (south) side of the foundation pit. Moreover, the maximum rate of the horizontal creep of the soil and the maximum rate of the creep caused by the ground settlement on the north side of the foundation pit are larger than those on the south side of the foundation pit; the maximum rate of the horizontal creep of the ordinary foundation pit is between the two. The active Earth pressure on the pit wall on the north side is higher than that on the south side of the foundation pit, and because of the surrounding unloading, passive Earth pressure is generated at the bottom of the pit wall on the south side of the foundation pit, which causes it to shift to the outside of the foundation pit. The settlement of the surrounding high-rise buildings and the settlement of the columns are all within the range of the alarm values; also, the buildings settle evenly. Due to the excavation and unloading on the south side of the foundation pit, the uplift of the columns is not considerable.


1997 ◽  
Vol 25 (4) ◽  
pp. 350-353 ◽  
Author(s):  
G. J. McHugh ◽  
D. J. C. Wild ◽  
J. H. Havill

Three groups of polyurethane central venous catheters (CVC) were infused daily for twenty days with 0.1 normal hydrochloric acid, 70% ethanol and normal saline (control) respectively to look for any changes in microscopic structural integrity. A 1 cm segment was cut from the distal end of each CVC daily. All sections were examined in a scanning electron microscope, looking for evidence either of damage to the lumen surface or of wall thinning. No significant damage to the lumen surfaces was observed with either treatment. Sporadic fine surface-pitting appeared late in the study without any clear temporal or treatment-related pattern. The mean CVC wall thickness did not change significantly over the study period (P=0.15). Qualitative softening of ethanol treated catheters was observed, and this finding limits the recommendations for the use of ethanol. 0.1N HCl does not compromise the structural safety of the catheters, and its use should be considered when polyurethane CVC become occluded.


2013 ◽  
Vol 838-841 ◽  
pp. 203-208
Author(s):  
Jie Chen ◽  
Dong Wang ◽  
Chun Lei Feng

This paper analyses the problem of locking value of anchor cable of pile anchor supporting of a deep foundation pit in the north of Kunming city. There are many influencing factors of locking value of anchor cable such as relaxation loss of anchor cable materials, tensioning system, pre-stress loss caused by anchorage friction, geological conditions and so on. And the author put forward the corresponding treatment measures for achieving the stability of supporting structure.


2014 ◽  
Vol 580-583 ◽  
pp. 636-640 ◽  
Author(s):  
Xu Tao Zhang ◽  
Qiang Yong Zhang ◽  
Chao Wang ◽  
You Fa Wang

The horizontal displacement of pit top and horizontal displacement in deep soil of underground garage deep foundation pit in Radio and TV centre of Shandong province was analyzed. Combing the deformation control value of foundation pit, we thought that the supporting structure was safe and reliable. The supporting structure could not only meet the strength requirements but also meet the deformation control requirements. This deep foundation pit was a successful case under complex conditions. Analyzing the variation rules between monitoring data and construction time, the instructive conclusions were obtained. The deformation of foundation pit external corner was largest. The external corner should be avoided in foundation pit. The dynamic loads around foundation pit had a great influence on the safety and stability of pit. The rainfall was disadvantage factors, so the construction of foundation pit should keep away from the rainy season. The foundation pit floor could limit soil deformation and improve the safety of pit. The pit floor should be constructed as early as possible.


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