STUDY OF THE COMPOSITE ACTION OF HOLLOWCORE PANELS USED IN GIRDER-SLAB SYSTEM

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Nathalie Roy ◽  
Serge Parent ◽  
Mélissa Barrière
Keyword(s):  
Prestressed Concrete ◽  
Large Scale ◽  
Steel Structure ◽  
Experimental Program ◽  
Steel Beams ◽  
Composite Action ◽  
Concrete Panels ◽  
Current Design ◽  
Main Components ◽  
Hot Rolled

Floor construction with precast hollowcore panels produced by Lafarge Precast Edmonton results in a commonly used girder-slab system. Continuity between the elements is ensured by bent rebars and shear studs. Once all these elements are installed, a structural concrete is poured between the reinforced concrete panels and over the entire floor. The extent of composite action between the rigid diaphragm and the steel beams is not known. Therefore, its potential benefit is not taken into account in the current design procedures for the steel structure. The main components of this research project are the following: an experimental program consisting of a series of 6 large-scale shear tests were carried out. The outcome of this research shows that there is a potential for a composite action between a hollowcore plank and a standard hot rolled W shape. It was found that there is enough confinement to develop the steel stud strength when the beam is connected to the precast prestressed concrete panels using a 1/2" shear stud embedded between the planks and under two to three inches of concrete topping.

Fiber Reinforced Fly Ash Concrete and Extreme Fires

2016 ◽  
Vol 722 ◽  
pp. 12-17 ◽  
Author(s):  
Miroslav Broucek ◽  
Michal Sejnoha ◽  
Pavel Reiterman
Keyword(s):  
Fly Ash ◽  
Temperature Distribution ◽  
Large Scale ◽  
Steel Fibers ◽  
Experimental Program ◽  
Fire Exposure ◽  
Concrete Panels ◽  
Fly Ash Concrete ◽  
Exposure Temperature ◽  
Fire Curve

The paper presents results from two large scale experiments on six concrete panels reinforced with steel fibers or bars obtained during an extensive experimental program aimed at possible application of cement reduced (fly ash replaced) concrete in the production of precast segmental linings for tunnels created by TBM. In particular, this paper focuses on the comparison of fire resistance of enhanced mixtures loaded by the modified RWS fire curve. The results from the experiments include spalling, overall damage of the surface, deformations during the fire exposure, temperature distribution and residual strength of the tested panels.

SOVIET SCIENTIFIC PERSONAL REPRESSIVE STATE APPARATUS AS AN OBJECT OF HISTORICAL SCIENCE OF SCIENCE STUDIES

2020 ◽  
pp. 27-35
Author(s):  
Alexander Allakhverdyan
Keyword(s):  
Science Policy ◽  
Large Scale ◽  
Science Studies ◽  
Soviet Science ◽  
State Repression ◽  
Developed Country ◽  
Systemic Analysis ◽  
State Apparatus ◽  
Dramatic Practice ◽  
Main Components

Numerous studies by Russian scientists and historians of science are devoted to the state science policy in the USSR and its well-known achievements, but not enough attention is paid to the negative, socially repressed aspects of the Soviet science policy. Repressions became one of the main components of the state's scientific and personnel policy in the Stalinist era. The systemic analysis of the development of Soviet science declared in the scientific literature, limited only by its indisputably outstanding achievements, without under-standing the origins, causes and mechanisms of the repressed state apparatus that operated in the same period, sharply reduces the overall picture of the reliability of the study of Soviet science. The purpose of the study is to comprehend the diverse and dramatic practice of state repression in the system of Soviet science, because in the world history of science no other developed country has experienced such large-scale and tragic events in the functioning of the scientific society.

Reuse of Wastewaters in Agriculture by Means of Sprinkler Irrigation on a Farmland Area of 3000 ha – Large Scale Experience in Germany

1986 ◽  
Vol 18 (9) ◽  
pp. 163-173
Author(s):  
R. Boll ◽  
R. Kayser
Keyword(s):  
Large Scale ◽  
Treatment Process ◽  
Treatment Plant ◽  
Sprinkler Irrigation ◽  
Paper Briefly ◽  
Treatment Results ◽  
Sewage Farm ◽  
Western Germany ◽  
Pre Treatment ◽  
Main Components

The Braunschweig wastewater land treatment system as the largest in Western Germany serves a population of about 270.000 and has an annual flow of around 22 Mio m3. The whole treatment process consists of three main components : a pre-treatment plant as an activated sludge process, a sprinkler irrigation area of 3.000 ha of farmland and an old sewage farm of 200 ha with surface flooding. This paper briefly summarizes the experiences with management and operation of the system, the treatment results with reference to environmental impact, development of agriculture and some financial aspects.

Comparison study of crack propagation in rubberized and conventional prestressed concrete sleepers using digital image correlation

2021 ◽  
pp. 095440972110205
Author(s):  
Guoqing Jing ◽  
Du yunchang ◽  
Ruilin You ◽  
Mohammad Siahkouhi
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Prestressed Concrete ◽  
Mouth Opening ◽  
Image Correlation ◽  
Crack Mouth Opening Displacement ◽  
Experimental Program ◽  
Pure Bending ◽  
Opening Displacement ◽  
Rubber Concrete

Rubber concrete (RC) has been confirmed to be suitable for concrete sleeper production. This paper studies the cracking behaviour of conventional and rubber-reinforced concrete sleepers based on the results of an experimental program. The cracking behaviour in the pure bending zone was analysed up to a load of 140 kN. The crack mouth opening displacement (CMOD) was accordingly measured using a digital image correlation (DIC) method. The DIC results show that the rubber prestressed concrete sleeper (RPCS) has a resistance against crack initiation that is 20% greater than that of the conventional prestressed concrete sleeper (CPCS) under the same loading condition; however, due to the higher crack growth rate of the RPCS, the first crack detected by the operator forms at 60 kN, which corresponds to a strength approximately 9% lower compared with the 65 kN load at which the first crack is detected in the CPCS. Before the first crack (60 kN), the RPCS has a deflection 35% lower than that of the CPCS, but after cracking, at loads of 80 kN, 100 kN and 140 kN, the RPCS has a deflection 15%, 4% and 24% higher than that of the CPCS, respectively.

Study on Welding Deformation and Residual Stress of H-Section Beam Based on Finite Element Method

2017 ◽  
Vol 753 ◽  
pp. 305-309 ◽  
Author(s):  
Xu Lu
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Finite Element ◽  
Source Parameters ◽  
Welding Process ◽  
Steel Structure ◽  
Bottom Plate ◽  
Welding Deformation ◽  
Element Simulation ◽  
Main Components

The welding H-section beam has good mechanical properties with its superior structure. So they become the main components of steel structure and have been widely used. In this paper, the welded H-section beam is used as the research object. The finite element simulation model is established. The heat source parameters are determined. The deformation of the steel due to the welding process is studied. The results show that the bottom plate and the bottom plate inward bending is about 2.32mm cause by welding process. The residual stress can reach 400MPa.

Extending span ranges and accelerating construction of spread slab beam bridges

2021 ◽  
Author(s):  
Dongqi Jiang
Keyword(s):  
Prestressed Concrete ◽  
Accelerated Bridge Construction ◽  
Span Length ◽  
Construction Operations ◽  
Concrete Panels ◽  
New Class ◽  
Low Profile ◽  
Speed Up ◽  
Beam Bridge ◽  
Precast Prestressed Concrete

<p>A new class of spread slab beam bridges has recently been developed and implemented in Texas. The research questions addressed in this paper are: how long can such a low profile bridge system span in either a simply supported or continuous form? And, can construction operations be accelerated, by design? An effective way to extend the span length is to utilize post-tensioning and to make the bridge continuous over several spans. In order to explore the maximum span limit, the design of a multi-span prestressed concrete spread slab beam bridge is investigated. In addition, a thicker and longer precast prestressed concrete panels (PCPs) that uses concentric pre-tensioned prestress is developed to facilitate accelerated bridge construction by reducing the need for field placement of deck reinforcement. It is shown that the span length may be extended from 15 m to 21 m as a continuous shallow profile bridge. The new solution for PCPs is verified to speed up field operations as compared to the traditional deck with stay-in-place PCPs and cast-in-place toppings.</p>

Capacity of prestressed concrete bridge decks under fatigue loading

2021 ◽  
Author(s):  
Eva O. L. Lantsoght ◽  
Cor van der Veen ◽  
Rutger Koekkoek ◽  
Henk Sliedrecht
Keyword(s):  
Prestressed Concrete ◽  
Large Scale ◽  
Fatigue Loading ◽  
Membrane Action ◽  
Variable Amplitude ◽  
Girder Bridges ◽  
Prestressed Girders ◽  
Series Of Experiments ◽  
Prestressed Concrete Bridge ◽  
Compressive Membrane Action

<p>In The Netherlands, existing slab-between-girder bridges with prestressed girders and thin transversely prestressed concrete decks require assessment. The punching capacity was studied in a previous series of experiments, showing a higher capacity thanks to compressive membrane action in the deck. Then, concerns were raised with regard to fatigue loading. To address this, two series of large-scale experiments were carried out, varying the number of loads (single wheel print versus double wheel print), the loading sequence (constant amplitude versus variable amplitude, and different loading sequences for variable amplitude), and the distance between the prestressing ducts. An S-N curve is developed for the assessment of slab-between-girder bridges. The experiments showed that compressive membrane actions enhances the capacity of thin transversely prestressed decks subjected to fatigue loading.</p>

EXPERIMENTAL INVESTIGATION OF CFRP STRENGTHENED I-SHAPED COLD FORMED STEEL BEAMS

2017 ◽  
Vol 79 (5) ◽  
Author(s):  
Nahushananda Chakravarthy ◽  
Sivakumar Naganathan ◽  
Jonathan Tan Hsien Aun ◽  
Sreedhar Kalavagunta ◽  
Kamal Nasharuddin Mustapha ◽  
...  
Keyword(s):  
Carrying Capacity ◽  
Experimental Results ◽  
Steel Beams ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Length Width ◽  
Cold Formed Steel ◽  
Formed Channel ◽  
Hot Rolled ◽  
Hot Rolled Steel

Cold formed steel differ from hot rolled steel by its lesser thickness and weight. The cold formed steel applicable in roof purlin, pipe racks and wall panels etc. Due its lesser wall thickness the cold formed steel member subjected to buckling. The enhancement of load carrying capacity of the cold formed steel member can be achieved by external strengthening of CFRP. In this study cold formed channel members connected back to back to form I shaped cross section using screws. These built up beam members were 300mm, 400mm and 500mm in length with 100mm screw spacing and edge distance of 50mm were chosen for testing. CFRP fabric cut according to length, width of built up beams and wrapped outer surface of beam using epoxy resin. Experiments were carried out in two sets firstly plain built up beams and secondly CFRP wrapped beams. The test results shows that increased load carrying capacity and reduction in deflection due to CFRP strengthening. Experimental results were compared with AISI standards which are in good agreement. Experimental results shows that CFRP strengthening is economic and reliable.

On the Evaluation and Consideration of Fracture Mechanical Notch Support Within a Creep Fatigue Lifetime Assessment

2018 ◽  
Author(s):  
Christian Kontermann ◽  
Henning Almstedt ◽  
Falk Müller ◽  
Matthias Oechsner
Keyword(s):  
Fatigue Loading ◽  
Experimental Program ◽  
Energy Market ◽  
Steam Turbines ◽  
Fatigue Lifetime ◽  
Global Strain ◽  
Creep Fatigue ◽  
Main Components ◽  
Flexible Operation ◽  
The Impact

Changes within the global energy market and a demand for a more flexible operation of gas- and steam-turbines leads to higher utilization of main components and raises the question how to deal with this challenge. One strategy to encounter this is to increase the accuracy of the lifetime assessment by quantifying and reducing conservatisms. At first the impact of considering a fracture mechanical notch support under creep-fatigue loading is studied by discussing the results of an extensive experimental program performed on notched round-bars under global strain control. A proposal how to consider this fracture mechanical notch support within a lifetime assessment is part of the discussion of the second part. Here, a theoretical FEM-based concept is introduced and validated by comparing the theoretical prediction with the results of the previously mentioned experimental study. Finally, the applicability of the developed and validated FEM-based procedure is demonstrated.

Researches on the Shear Deformation of Joints Domain of Beam-to-Column Connection of Light Steel Structure

2012 ◽  
Vol 256-259 ◽  
pp. 1004-1007
Author(s):  
Xi Bing Hu ◽  
Jian Hua Lu
Keyword(s):  
Finite Element Method ◽  
Shear Deformation ◽  
Design Method ◽  
Steel Structure ◽  
Structure Calculation ◽  
The Finite Element Method ◽  
Mechanics Performance ◽  
Current Design ◽  
Internal Forces ◽  
Complex Parts

The joint domain of beam-to-column connection is very complex parts under loading, which plays an important role in transferring internal forces in light steel structure, such as moment, shear, axial force and so on. Considering the influence of its shear deformation in the structure calculation can help us to reflect the actual mechanics performance and evaluate precisely practical bearing capacity of the structure. According to the actual characteristics of beam-to-column connection, the author established some models of its joint domain, and used the finite element method to analyze and calculate shear deformation of these models. Meanwhile, the author researched the influence of the changes of various parameters to its shear deformation, and provided beneficial suggestions for revising the current design method of light steel structure finally.

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