scholarly journals Two Post-tensioned Thin Folded Plates Designed by E. Torroja for San Nicolás Church

2017 ◽  
Author(s):  
Ernesto Fenollosa ◽  
Begoña Serrano ◽  
Adolfo Alonso ◽  
Fernando Arnau
Keyword(s):  
Horizontal Displacement ◽  
Element Model ◽  
Biaxial Bending ◽  
Long Span ◽  
Strength Capacity ◽  
Innovative Solution ◽  
Technical Advances ◽  
Concrete Elements ◽  
Mutually Independent ◽  
Post Tensioned

The long-span structure of the San Nicolás church was designed in 1959 by the renowned engineer E. Torroja. His innovative solution consists of two Z-shaped folded plates mutually independent spanning 29 m. In this paper the technical advances used by the engineer to carry out its daring structure are explained. A series of ribs provide stiffness to the slabs facing biaxial bending and torsion and support cantilevered roof. The set of post-tensioned tendons contribute to the strength capacity of the slabs as well as avoid the cracking of concrete. Rotation and the horizontal displacement of the plates are released by the twofold articulation of the main frame. The simplified structural design carried out by the engineer is explained and his results are compared with the structural analysis obtained by a virtual finite element model. The aggressive environment caused corrosion in reinforced concrete elements, but not in the post-tensioned concrete plates.

Character Analysis of Balance and Imbalance of Varying Rigidity of Rigid Pile Composite Foundation under Seismic Load

2014 ◽  
Vol 1065-1069 ◽  
pp. 19-22
Author(s):  
Zhen Feng Wang ◽  
Ke Sheng Ma
Keyword(s):  
Finite Element ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Element Model ◽  
Composite Foundation ◽  
Seismic Load ◽  
Seismic Loads ◽  
Element Analysis ◽  
Rigid Pile ◽  
Rigid Pile Composite Foundation

Based on ABAQUS finite element analysis software simulation, the finite element model for dynamic analysis of rigid pile composite foundation and superstructure interaction system is established, which selects the two kinds of models, by simulating the soil dynamic constitutive model, selecting appropriate artificial boundary.The influence of rigid pile composite foundation on balance and imbalance of varying rigidity is analyzed under seismic loads. The result shows that the maximum bending moment and the horizontal displacement of the long pile is much greater than that of the short pile under seismic loads, the long pile of bending moment is larger in the position of stiffness change. By constrast, under the same economic condition, the aseismic performance of of rigid pile composite foundation on balance of varying rigidity is better than that of rigid pile composite foundation on imbalance of varying rigidity.

Research on Friction between Grade Flat Approach Slab and Sliding Material in Jointless Bridges

2019 ◽  
Author(s):  
Yufeng Tang ◽  
Bruno Briseghella ◽  
Junqing Xue ◽  
Peiquan Zhang ◽  
Fuyun Huang ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Life Cycle Cost ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Element Model ◽  
Expansion Joints ◽  
Approach Slab ◽  
Jointless Bridges ◽  
Friction Function ◽  
The Mathematical Model

<p>The application of jointless bridges has been increasing year by year, because it could reduce the life‐cycle cost and improve the riding comfort. The approach slab in jointless bridges does not only have the function of road transition which is the same as the approach slab in bridges with expansion joints, but also transfer and absorb the deformation produced by the thermal expansion and contraction of the girder. The Grade Flat Approach Slab (GFAS) horizontally placed on the subgrade is one of the most common types of the approach slab in jointless bridges. The material placed between GFAS and subgrade should be able to properly slide to reduce the stress in GFAS. The friction coefficient between GFAS and sliding material is an important parameter affecting the mechanical behavior of GFAS in jointless bridges. In this paper, the tests of GFAS with different sliding materials subjected to horizontal displacement were conducted to obtain the corresponding friction coefficients (from 0.34 to 0.68). The mathematical model of bilinear spring could be adapted to simulate the friction function between GFAS and different sliding materials. One Deck‐Extension Bridge (DEB) that is one type of jointless bridges was chosen as a case study. The finite element model was implemented by using Midas‐Civil software. The influence of GFAS with different sliding materials on the mechanical properties of DEB under temperature variation was investigated. It can be concluded that the influence of the friction coefficient between GFAS and sliding material on the bending moment of DEB should be taken into account.</p>

Dynamic Characteristics of a Long-Span Cable-Stayed Bridge

2011 ◽  
Vol 480-481 ◽  
pp. 1496-1501
Author(s):  
Liu Hui
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Iteration Method ◽  
Natural Frequencies ◽  
Element Model ◽  
Vibration Modes ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Subspace Iteration ◽  
Floating System

In order to study the dynamic characteristics of a super-long-span cable-stayed bridge which is semi-floating system, the spatial finite element model of this cable-stayed bridge was established in ANSYS based on the finite element theory.Modal solution was conducted using subspace iteration method, and natural frequencies and vibration modes were obtained.The dynamic characteristics of this super-long-span cable-stayed bridge were then analyzed.Results showed that the super-long-span cable-stayed bridge of semi-floating system has long basic cycle, low natural frequencies, dense modes and intercoupling vibration modes.

Ultrasonic imaging of post-tensioned concrete elements

2008 ◽  
pp. 215-216 ◽  
Author(s):  
F Mielentz ◽  
H Wiggenhauser ◽  
M Friese ◽  
B Gräfe ◽  
B Milmann ◽  
...  
Keyword(s):  
Ultrasonic Imaging ◽  
Concrete Elements ◽  
Post Tensioned

scholarly journals Comparison of Dynamic Characteristics between Small and Super-Large Diameter Cross-River Twin Tunnels under Train Vibration

2021 ◽  
Vol 11 (16) ◽  
pp. 7577
Author(s):  
Lin Wu ◽  
Xiedong Zhang ◽  
Wei Wang ◽  
Xiancong Meng ◽  
Hong Guo
Keyword(s):  
Dynamic Characteristics ◽  
Large Diameter ◽  
Horizontal Displacement ◽  
Element Model ◽  
Vertical Displacement ◽  
Decisive Factor ◽  
Cross River ◽  
Static Responses ◽  
Train Vibration ◽  
Twin Tunnels

Train vibration from closely aligned adjacent tunnels could cause safety concerns, especially given the soaring size of the tunnel diameter. This paper established a two-dimensional discrete element model (DEM) of small (d = 6.2 m) and super-large (D = 15.2 m) diameter cross-river twin tunnels and discussed the dynamic characteristics of adjacent tunnels during the vibration of a train that runs through the tunnel at a speed of 120 km/h. Results in the D tunnel showed that the horizontal walls have the same horizontal displacement (DH) and the vertical walls have the same vertical displacement (DV). The stress state of the surroundings of the D tunnel is the decisive factor for DH, and the distance from the vibration point to the measurement point is the decisive factor for DV. Results in the comparison of the d and D tunnels showed that the D tunnel is more stable than the d tunnel with respect to two aspects: the time the tunnel reaches the equilibrium state and the vibration amplitude of the structure’s dynamic and static responses. The dynamic characteristic of the d and D tunnel is significantly different. This research is expected to guide the design and construction of large diameter twin tunnels.

scholarly journals Probabilistic Assessment of the Safety of Main Cables for Long-Span Suspension Bridges considering Corrosion Effects

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Hao Tian ◽  
Jiji Wang ◽  
Sugong Cao ◽  
Yuanli Chen ◽  
Luwei Li
Keyword(s):  
Probability Model ◽  
Steel Wire ◽  
Suspension Bridge ◽  
Element Model ◽  
Traffic Load ◽  
Suspension Bridges ◽  
Accelerated Corrosion ◽  
Long Span ◽  
Accelerated Corrosion Tests ◽  
Main Cables

This paper presents a reliability analysis to assess the safety of corroded main cables of a long-span suspension bridge. A multiscale probability model was established for the resistance of the main cables considering the length effect and the Daniels effect. Corrosion effects were considered in the wire scale by relating the test results from accelerated corrosion tests to the corrosion stages and in the cable scale by adopting a corrosion stage distribution of the main cable section in NCHRP Report 534. The load effects of temperature, wind load, and traffic load were obtained by solving a finite element model with inputs from in-service monitoring data. The so-obtained reliability index of the main cables reduces significantly after operation for over 50 years and falls below the design target value due to corrosion effects on the mechanical properties of the steel wire. Multiple measures should be taken to delay the corrosion effects and ensure the safety of the main cables in the design service life.

Numerical analysis of soil deformation behind the reaction wall of an open caisson induced by horizontal parallel pipe-jacking construction

2015 ◽  
Vol 52 (12) ◽  
pp. 2008-2016 ◽  
Author(s):  
Yang Sun ◽  
Jing-bo Su ◽  
Xiao-he Xia ◽  
Zheng-liang Xu
Keyword(s):  
Reaction Force ◽  
Soil Surface ◽  
Horizontal Displacement ◽  
Element Model ◽  
Deformation Analysis ◽  
Burial Depth ◽  
Maximum Displacement ◽  
Obvious Effect ◽  
Simple Loading ◽  
Pipe Jacking

The disturbance of the soil behind the reaction wall of an open caisson can affect the efficiency and safety of jacking operation and control. This study focuses on the deformation of the soil mass behind the reaction wall used to support the jack. The stress–strain relationship of the soil behind the reaction wall was analysed, providing a theoretical basis for determining the most unfavourable combination of reactive forces using a computational model. A three-dimensional finite element model for this problem was developed, and a simple loading scenario was implemented. In addition, the mechanism of the deformation of the soil induced by horizontal parallel pipe jacking was also analysed. The results showed that for the soil behind the reaction wall of the open caisson, the uplift deformation of the soil surface increased initially and later gradually decreased, eventually achieving stability. The reaction force had a relatively obvious effect on the deformation of the soil within the range of the reaction wall burial depth and the horizontal displacement of the soil along the length of the reaction wall. The maximum displacement occurred near the axis of symmetry of the reaction wall. In addition, to consider the cyclic characteristics of the reaction force, the shakedown theorem is introduced to the deformation analysis of the soil and compared with the results obtained from simple loading. It was shown that the two deformation analysis methods have certain scopes of application, depending on the individual engineering requirements.

scholarly journals Structural Health Monitoring of the Scaffolding Dismantling Process of a Long-Span Steel Box Girder Viaduct Based on BOTDA Technology

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Yong Ding ◽  
Feng Xiao ◽  
Weiwei Zhu ◽  
Tao Xia
Keyword(s):  
Health Monitoring ◽  
Strain Distribution ◽  
Time Domain Analysis ◽  
Element Model ◽  
Box Girder ◽  
Bridge Health Monitoring ◽  
Long Span ◽  
Steel Box Girder ◽  
Optical Time ◽  
Distributed Optical Fiber

In this study, a distributed optical fiber sensing technique based on Brillouin optical time-domain analysis (BOTDA) is used to construct a complete bridge health monitoring system by continuously laying distributed sensing fiber lines in a steel box girder. The bridge scaffolding dismantling process is monitored to study the variation of the strain distribution. Additionally, a bridge finite element model is built to simulate the bridge scaffolding removed condition, and the strain distribution of the long-span steel box girder viaduct after scaffolding dismantling is compared with the measured values. This study provides a reference for monitoring the scaffolding dismantling process based on BOTDA technology.

scholarly journals Performance of Notched Connectors for CLT-Concrete Composite Floors

Buildings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 122
Author(s):  
Minh Van Thai ◽  
Sylvain Ménard ◽  
Sidi Mohammed Elachachi ◽  
Philippe Galimard
Keyword(s):  
Element Model ◽  
Maximum Load ◽  
Edge Length ◽  
Experimental Results ◽  
Notch Depth ◽  
Long Span ◽  
Brittle Rupture ◽  
Screw Length ◽  
Floor Systems ◽  
And Behavior

CLT-concrete composite floor systems are a solution for timber buildings with a long-span floor. It yields a reduction of carbon footprint and even eco-friendly structure at the end of its service life. This study will evaluate the structural performance of notched connectors in the CLT-concrete composite floor, comprised of the serviceability stiffness, maximum load, and behavior at failure. The parameters of the test plan are the loaded edge length, the notch depth, the concrete thickness, and the screw length. Other secondary variables are also assessed, such as different loading sequences, speed of test, and timber moisture content. Experimental results prove that the performance of the connector depends significantly but not linearly on the notch depth and the length of the loaded edge. The connector with a deeper notch and a shorter heel will be stiffer and more robust, but it also tends to have a brittle rupture. The test results also help validate a solution for deconstructable connector systems. A nonlinear finite element model of the connector is built and validated versus the experimental results. It yields reasonably good predictions in terms of resistance and can capture the load-slip relationship.

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