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Su J.,Hong Kong Polytechnic University | Xia Y.,Hong Kong Polytechnic University | Xu Y.,Hong Kong Polytechnic University | Zhao X.,Tongji Architectural Design Group Co. | Zhang Q.,Tongji University
Advances in Structural Engineering | Year: 2014

Excessive and unexpected settlement of supertall buildings during the construction stage may affect structural safety. Floor settlement monitoring is imperative during the structural construction. The current practice is to measure floor settlement within a specific time frame and then compensate for the elevation error in the next construction stage. This posterior manner is inaccurate because it does not take account of measurement error and the real settlement in the next construction stage. This paper presents a Kalman filter based settlement monitoring approach with the aid of forward construction stage analysis. The settlement of floors in the next stage is predicted with the forward construction stage analysis. Consequently the elevation of the floor to be constructed can be pre-determined. The proposed method is demonstrated through construction settlement monitoring of the 632-m tall Shanghai Tower. The structure will be the tallest supertall building of China upon completed in 2014. It shows that this method can improve the accuracy of pre-determined elevation of supertall buildings.

Dong X.,Key Laboratory of Concrete and Pre stressed Concrete Structures of Ministry of Education | Dong X.,Tongji Architectural Design Group Co. | Ye J.-H.,Key Laboratory of Concrete and Pre stressed Concrete Structures of Ministry of Education
Gongcheng Lixue/Engineering Mechanics | Year: 2014

Through Particle Image Velocimetry (PIV), flow visualization of separation bubble and conical vortices on large-span flat and saddle roofs was conducted in a wind tunnel. The streamline and vorticity field of visual planes on large-span roofs were derived by PIV. The influence of wind direction and roof curvature on the appearance of conical vortices was discussed. The results indicate that separated bubble occurs when the flow is normal to the leading edge of the flat roof. The location of the vortex core is corresponding to the negative peak vorticity. For cornering flow, conical vortices are observed near the leading edge of the flat roof and the saddle roofs whose high points are windward. When the wind direction changes from along the diagonal to deviating from the diagonal of the roofs, the conical vortex close to the approaching flow changes to be more oblong shaped. The negative vorticity is concentrated on the roof surface, while the peak is near the leading edge and around the vortices. At the same wind direction, a greater roof curvature leads to a larger angle between the vortex axis of conical vortices and the leading edge of the saddle roof. The instantaneous streamline of the visual planes illustrates that conical vortices are resizing and swaying constantly, which reveals its intermittent characteristic. ©, 2014, Gongcheng Lixue/Engineering Mechanics. All right reserved.

Yao W.,Tianjin Chengjian University | Li Z.,Tongji University | Zhao Q.,Tongji University | Lu Y.,Tongji Architectural Design Group Co. | Lu R.,Tongji University
Energy Conversion and Management | Year: 2015

Through the analysis of distribution of diffuse radiation in the sky, the sky diffuse radiation is divided into four zones. Based on the concept of radiation intensity and solid angle, the corresponding integral equation is established in each zone to build a new theoretical model of anisotropic diffuse radiation. Radiation enhancement coefficients in the new theoretical model are solved from the instantaneous diffuse radiation data received by 30°, 45°, 60° inclined planes, then new model and existing models are compared with the diffuse radiation data received by 90° inclined planes. The results demonstrate that for existing models, Perez model is the most accurate, followed by Liu and Jordan model. Among the second generation models, Klucher model, Hay model, Skartveit and Olseth model are relatively accurate. While compared with existing models, NADR model is more consistent with the measured values. Further comparative analysis shows that for east and north orientations, Perez model and NADR model are more accurate; for south and west orientations, Liu and Jordan model and NADR model are more accurate. Klucher model is well agreed with the measured data in different inclinations. Hay model and Skartveit and Olseth model are relatively accurate on 30° tilt surface, and Temps and Coulson model is also relatively accurate on 45° tilt surface. NADR model is in good agreement with the measured data on 60° and 90° tilt surface. On the whole, NADR model is more accurate than the existing models. © 2015 Elsevier Ltd. All rights reserved.

Li X.,Tongji Architectural Design Group Co.
Journal of Earthquake Engineering and Engineering Vibration | Year: 2014

Earthquake action is often a major factor of bridge design controlling for large span concrete continuous girder bridge in high seismic risk zone. It is a vexed question for engineers to choose a reasonable seismic isolation design. A three span continuous girder bridge (3 ×30m) in Quan Zhou is analyzed in this paper. Finite element model is built with double spherical aseismic bearing, lead rubber bearing (LRB) and cable-sliding friction aseismic bearing (CSFAB) respectively. The isolation effect of different bearings is studied by nonlinear time history analysis. Results indicate that, CSFAB can not only reduce the internal force at the bottom of the pier, but also have great advantages in controlling the relative displacement between girder and pier. Thus CSFAB is adequate to meet the demands of structural seismic performance.

Li J.,Nanjing Southeast University | Ni F.,Nanjing Southeast University | Jin J.,Tongji Architectural Design Group Co. | Zhou Z.,Nanjing Southeast University
Road Materials and Pavement Design | Year: 2016

With the government promoting use of hot in-place recycling (HIR) in China, the performance of HIR pavement has become a topic of intensive study. HIR processes had been using rejuvenator to restore properties of aged binder in the past, but it was found that rejuvenator is not sufficient in reconstituting the physical and chemical properties of aged polymer-modified asphalt, and that it is inclined to increase rutting potential. Sryrene–butadiene rubber (SBR) latex was then brought up as a proper substitute for rejuvenator in recent years. In this paper, both rejuvenator and SBR latex are evaluated and compared in the HIR process with modified asphalt binder. Comprehensive tests in laboratory and field trials were conducted to evaluate the properties of recycled binder and recycled mixtures. The results show that SBR latex increases the viscosity of aged binder, meanwhile it improves the rutting resistance and fatigue cracking resistance of reclaimed asphalt pavement (RAP) significantly, and that rejuvenator has adverse effect on both rutting and fatigue cracking resistance of RAP. Also SBR latex shows better application performance than rejuvenator in the moisture susceptibility and low-temperature cracking resistance of RAP. Both HIR trials with rejuvenator and SBR latex have maintained a high level of service since open to traffic, but trials with SBR latex is observed to be more promising in rutting resistance than those with rejuvenator. © 2016 Taylor & Francis

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