scholarly journals Experimental dynamic analysis of the arch road bridge

2021 ◽  
Vol 906 (1) ◽  
pp. 012061
Author(s):  
Tomáš Plachy ◽  
Michal Polák ◽  
Pavel Ryjáček ◽  
Milan Talich ◽  
Jan Havrlant ◽  
...  
Keyword(s):  
Natural Frequencies ◽  
Road Traffic ◽  
Radar Interferometry ◽  
Horizontal Load ◽  
Classical Approach ◽  
Load Bearing ◽  
The Third ◽  
Bridge Span ◽  
Main Bridge ◽  
Bearing Structure

Abstract The paper presents an experimental dynamic analysis of the existing road bridge across the Labe river at Valy village in the Czech Republic. The observed structure is a bridge with 6 spans 23.1 m, 31.5 m, 84.0 m, 31.5 m and 23.1 m long. The horizontal load-bearing structure is a composite structure with two main steel girders and a lower reinforced concrete deck. The load-bearing structure is reinforced in the main span by the arch, this structural system is also called the Langer beam. The experiment was realized in three stages. The first one was performed in May 2020 before its opening, the second stage of the described experiment was realized in August 2020 and the third one was carried out in April 2021. The main purpose of the first stage was to determine in detail the natural frequencies and mode shapes of the whole bridge horizontal load-bearing structure also including the arch. The electrodynamic shaker, that was located on the bridge deck in the quarter of the main bridge span, was used for excitation of the bridge vibration. The measured characteristics of the natural vibration were compared with the calculated ones. Based on this comparison, the theoretical bridge model was verified. Basic objective of the second experiment stage was to verify new approach to dynamic response measurement – radar interferometry realized by two synchronized radars. The vibrations of the bridge caused by the standard road traffic and also by pedestrians were observed concurrently by both radar interferometry and classical approach realized by high sensitive piezoelectric accelerometers. The experiment was focused on the main span of the bridge only and the levels of forced vibration were observed primarily. However, the fundamental natural frequencies were also evaluated. The third stage was carried out by classical approach only. Again, the bridge vibration caused by the usual road traffic and pedestrians were measured in the main bridge span only because this section of the bridge was the most dynamically sensitive. Again, the levels of forced vibration were observed and the fundamental natural frequencies were determined. The evaluated natural frequencies from all three experiment stages were consequently compared.

Experimental Behavior of Masonry Vaults Strengthened with Thin Extradoxal or Intradoxal Layer of Fiber Reinforced Lime Mortar

2017 ◽  
Vol 747 ◽  
pp. 274-281 ◽  
Author(s):  
Natalino Gattesco ◽  
Ingrid Boem ◽  
Alessandra Gubana ◽  
Davide Menegon ◽  
Norman Bello ◽  
...  
Keyword(s):  
Thin Layer ◽  
Experimental Tests ◽  
Horizontal Load ◽  
Actual Behavior ◽  
Cyclic Tests ◽  
Lime Mortar ◽  
Numerical Investigations ◽  
The Third ◽  
Loading Patterns ◽  
Masonry Vaults

The results of a first experimental research program on masonry vaults strengthened by means of GFRP meshes embedded in a thin layer of lime mortar, are herein presented. The tests were designed to reproduce the pattern of a transversal horizontal load proportional to the vault self-weight. The typical simplified loading patterns generally used for the experimental tests concern concentrated vertical loads at the crown section or at 1/4 of the span, but some numerical investigations evidenced that these configurations are not able to reproduce the actual behavior and the effectiveness of the reinforcement. So a specific rig was designed to apply the horizontal load pattern.Solid brick masonry barrel vaults were considered (thickness 120 mm, arch span 4000 mm, arch rise/radius = 0.75). Three quasi-static cyclic tests were performed: the first concerned an unreinforced vault, the second a vault reinforced at the extrados through the application of a mortar coating reinforced with a GFRP mesh and the third reinforced at the intrados surface with the same technique. The experimental results demonstrated the technique effectiveness and the important increment of ductility of the vaults.

scholarly journals Reliability as a Key Driver for a Sustainable Design of Adaptive Load-Bearing Structures

2022 ◽  
Vol 14 (2) ◽  
pp. 895
Author(s):  
Dshamil Efinger ◽  
Andreas Ostertag ◽  
Martin Dazer ◽  
David Borschewski ◽  
Stefan Albrecht ◽  
...  
Keyword(s):  
Environmental Sustainability ◽  
Construction Materials ◽  
Internal Stresses ◽  
Elastic Model ◽  
Load Spectrum ◽  
Operating Life ◽  
Load Bearing ◽  
Linear Elastic ◽  
High Rise ◽  
Bearing Structure

The consumption of construction materials and the pollution caused by their production can be reduced by the use of reliable adaptive load-bearing structures. Adaptive load-bearing structures are able to adapt to different load cases by specifically manipulating internal stresses using actuators installed in the structure. One main aspect of quality is reliability. A verification of reliability, and thus the safety of conventional structures, was a design issue. When it comes to adaptive load-bearing structures, the material savings reduce the stiffness of the structure, whereby integrated actuators with sensors and a control take over the stiffening. This article explains why the conventional design process is not sufficient for adaptive load-bearing structures and proposes a method for demonstrating improved reliability and environmental sustainability. For this purpose, an exemplary adaptive load-bearing structure is introduced. A linear elastic model, simulating tension in the elements of the adaptive load-bearing structure, supports the analysis. By means of a representative local load-spectrum, the operating life is estimated based on Woehler curves given by the Eurocode for the critical notches. Environmental sustainability is increased by including reliability and sustainability in design. For an exemplary high-rise adaptive load-bearing structure, this increase is more than 50%.

scholarly journals Analysis of Timoshenko beam with Koch snowflake cross-section and variable properties in different boundary conditions using finite element method

2021 ◽  
Vol 13 (11) ◽  
pp. 168781402110609
Author(s):  
Hossein Talebi Rostami ◽  
Maryam Fallah Najafabadi ◽  
Davood Domiri Ganji
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Natural Frequency ◽  
Cross Section ◽  
Timoshenko Beam ◽  
Natural Frequencies ◽  
Variable Properties ◽  
The Third ◽  
Koch Snowflake

This study analyzed a Timoshenko beam with Koch snowflake cross-section in different boundary conditions and for variable properties. The equation of motion was solved by the finite element method and verified by Solidworks simulation in a way that the maximum error was about 2.9% for natural frequencies. Displacement and natural frequency for each case presented and compared to other cases. Significant research achievements illustrate that if we change the Koch snowflake cross-section of the beam from the first iteration to the second, the area and moment of inertia will increase, and we have a 5.2% rise in the first natural frequency. Similarly, by changing the cross-section from the second iteration to the third, a 10.2% growth is observed. Also, the hollow cross-section is considered, which can enlarge the natural frequency by about 26.37% compared to a solid one. Moreover, all the clamped-clamped, hinged-hinged, clamped-free, and free-free boundary conditions have the highest natural frequency for the Timoshenko beam with the third iteration of the Koch snowflake cross-section in solid mode. Finally, examining important physical parameters demonstrates that variable density from a minimum value to the standard value along the beam increases the natural frequencies, while variable elastic modulus decreases it.

Multi-condition optimization design of main load bearing structure of optical small satellite

2017 ◽  
Vol 46 (12) ◽  
pp. 1218004
Author(s):  
谭陆洋 Tan Luyang ◽  
王 栋 Wang Dong ◽  
李 林 Li Lin ◽  
谷 松 Gu Song ◽  
孔 林 Kong Lin
Keyword(s):  
Optimization Design ◽  
Small Satellite ◽  
Load Bearing ◽  
Condition Optimization ◽  
Bearing Structure

The Bridge over the Chomutovka River Valley

2017 ◽  
Vol 259 ◽  
pp. 130-134
Author(s):  
Radim Cihlář ◽  
Martin Nožička ◽  
Jakub Aubrecht
Keyword(s):  
Czech Republic ◽  
Pile Foundation ◽  
River Valley ◽  
Box Girder ◽  
The Czech Republic ◽  
Load Bearing ◽  
The Road ◽  
Planning Agency ◽  
The Village ◽  
Bearing Structure

The purpose of this article is to describe the construction of the bridge spanning the Chomutovka river valley as a part of the road I/27 bypassing the village of Velemyšleves. The investor of this project is Ředitelství silnic a dálnic ČR, správa Chomutov (Directorate for Roads and Motorways of the Czech Republic, division Chomutov). The general constructor of the entire project is the association of companies Silnice Group a.s. and AZ sanace a.s., the constructor of the foundations and the pile foundation is AZ Sanace a.s. and the constructor of the bridge is SMP CZ, a.s. The project execution documentation was carried out by the planning agency NOVÁK & PARTNER s.r.o. The designer and lead construction engineer of the project is Doc. Ing. Lukáš Vráblík, Ph.D.The structure is a seven-span bridge with a total length of 537 m. The load bearing structure, constructed using cantilever casting and supporting construction, consists of a seven-span continuous box girder with two frame connections. The whole structure is to be opened for public use by the end of this year.

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