Design of Shear Pocket Connections in Full-depth Precast Concrete Bridge Deck Systems

Design of Shear Pocket Connections in Full-depth Precast Concrete Bridge Deck Systems
Author: Raed Tawadrous
Publisher:
Total Pages: 0
Release: 2017
Genre: Bridges
ISBN: 9781369834918

The main objective of this research is to develop procedures/criteria for designing HSS-formed shear pockets with clustered shear connectors for full-depth precast concrete deck systems. These procedures/criteria will assist in sizing shear connectors, selecting shear pocket dimensions and HSS thickness, and determining pocket anchorage and reinforcement necessary to maximize the connection capacity while allowing adequate construction tolerance. Experimental investigation (push-off testing) and finite element analysis (FEA) were performed to validate the developed design procedures/criteria. Analysis and testing results validated the adequacy of the developed design procedures/criteria for HSS-formed shear pocket connections. In addition, the results of 162 push-off tests conducted by the author and others obtained from the literature were used to check the feasibility of using current interface shear prediction models provided by AASHTO LRFD, fib MC 2010, Eurocode-2, and CSA-S6 design codes. Comparisons indicated that existing code provisions are applicable for predicting interface shear resistance of clustered shear connectors with different levels of accuracy.

Wie ist der Beruf eines ev. luth. Gemeindeschullehrers anzusehen?.

Wie ist der Beruf eines ev. luth. Gemeindeschullehrers anzusehen?.
Author:
Publisher:
Total Pages: 33
Release: 1900
Genre: Teachers
ISBN: 9781463661373

I was broke. I had not eaten for three days. I had walked the streets for three nights. Every fibre of my being, every precept of my home training protested against and would not permit my begging. I saw persons all about me spending money for trifles, or luxuries. I envied the ragged street urchin as he took a nickel in exchange for a newspaper and ran expectantly to the next pedestrian. But I was broke and utterly miserable.Have you ever been broke? Have you ever been hungry and miserable, not knowing when or where you were going to get your next meal, nor where you were going to spend your next night?Have you ever tramped holes in your shoes in a tiresome, discouraging effort to get work, meeting rebuff and insults in return for your earnestness and sincerity, and encountering an utter lack of an understanding of your crying necessity in those with whom you have pleaded for a chance?Have you ever felt as though the world itself were against you and that a mistake had been made by Nature in inflicting you with life?If you have not felt each and all of these things it will, perhaps, be futile for you to read what they brought to one who has felt them, and it will be difficult for you to tolerate any thought of extenuation for what happened. Thousands of persons have felt these thoughts, have suffered these experiences, but very few have done what I did; at all events, very few have done what I did and then told about it, as I am going to tell.Few crimes are committed from choice. The number of professional criminals is small, amazingly small, in comparison with the number who are criminals of circumstance. But society makes no distinction; the man who steals because he is hungry, and too proud or squeamish to beg, is classed with the thug who waylays you at night and takes your money by persuasion of an ugly .44-caliber "smoke-wagon" held within an inch of your brain, and with money jingling in his own pocket at the moment.The first is an unfortunate human being driven to commit an act which he abhors; the second a dangerous menace to humankind and organized society. I belonged to the unprofessional class. And despite a long term in prison, I am not yet a criminal. Every atom of my body, each vibration of my mind, revolts at the thought of crime. Yet I committed burglary; also I have a big, warm tolerance for other men who have committed burglary, or other crimes, no matter who they may be. Do not mistake me-I am not seeking to apotheosize the offender against the law; far from it. But I know that all men are human-even the men in convict stripes and shaven heads.Why shouldn't I know? Haven't I been one of them?Didn't I violate the sacredness of a home in the dead of night, and didn't I spend long years in the penitentiary?Who knows if I don't? As I look back I wonder what has been accomplished by my imprisonment. Perhaps before this series of sketches is done some of you may discover what has been accomplished in my individual case. But what is being accomplished in the thousands of other and more unconscionable cases? Perhaps you do not care; possibly you may feel that it is none of your concern; that you pay taxes for protection, and that you cannot be held accountable for the shortcomings of others or for the inhuman and illogical system that enhances the certainty of still greater violation of man-made laws.Be that as it may, you are still responsible; and you are not protected. I was broke and utterly miserable. True, there were thousands of others just as miserable-I realized that -but I was myself, I was no one else save myself, and I had a nickel with a hole in it in my pocket. Never mutilate a coin of the realm. It may fall into the hands of a starving man or woman and prove the last argument in favor of crime-or suicide. It was nearing midnight and the possibility of escaping another night in the streets growing slimmer with each passing moment. Somehow I felt that something....

Experimental Evaluation of Full Depth Precast/prestressed Concrete Bridge Deck Panels

Experimental Evaluation of Full Depth Precast/prestressed Concrete Bridge Deck Panels
Author: Mohsen A. Issa
Publisher:
Total Pages: 278
Release: 2002
Genre: Concrete bridges
ISBN:

A literature review concerning the objectives of the project was completed. A significant number of published papers, reports, etc., were examined to determine the effectiveness of full depth precast panels for bridge deck replacement. A detailed description of the experimental methodology was developed which includes design and fabrication of the panels and assembly of the bridge. The design and construction process was carried out in cooperation with the project Technical Review Panel. The major components of the bridge deck system were investigated. This includes the transverse joints and the different materials within the joint as well as composite action. The materials investigated within the joint were polymer concrete, non-shrink grout, and set-45 for the transverse joint. The transverse joints were subjected to direct shear tests, direct tension tests, and flexure tests. These tests exhibited the excellent behavior of the system in terms of strength and failure modes. Shear key tests were also conducted. The shear connection study focused on investigating the composite behavior of the system based on varying the number of shear studs within a respective pocket as well as varying the number of pockets within a respective panel. The results indicated that this shear connection is extremely efficient in rendering the system under full composite action. Finite element analysis was conducted to determine the behavior of the shear connection prior to initiation of the actual full scale tests. In addition, finite element analysis was also performed with respect to the transverse joint tests in an effort to determine the behavior of the joints prior to actual testing. The most significant phase of the project was testing a full-scale model. The bridge was assembled in accordance with the procedures developed as part of the study on full-depth precast panels and the results obtained through this research. The system proved its effectiveness in withstanding the applied loading that exceeded eight times the truck loading in addition to the maximum negative and positive moment application. Only hairline cracking was observed in the deck at the maximum applied load. Of most significance was the fact that full composite action was achieved between the precast panels and the steel supporting system, and the exceptional performance of the transverse joint between adjacent panels.

Recommendations for the Connection Between Full-depth Precast Bridge Deck Panel Systems and Precast I-beams

Recommendations for the Connection Between Full-depth Precast Bridge Deck Panel Systems and Precast I-beams
Author:
Publisher:
Total Pages: 75
Release: 2007
Genre: Bridges
ISBN:

Precast bridge deck panels can be used in place of a cast-in-place concrete deck to reduce bridge closure times for deck replacements or new bridge construction. The panels are prefabricated at a precasting plant providing optimal casting and curing conditions, which should result in highly durable decks. Precast panels can be either full-depth or partial-depth. Partial-depth panels act as a stay-in-place form for a cast-in-place concrete topping. This study investigated only the behavior of full-depth precast panels. The research described in this report had two primary objectives. The first was to develop a performance specification for the grout that fills the haunch between the top of the beam and the bottom of the deck panel, as well as the horizontal shear connector pockets and the panel-to-panel joints. Tests were performed using standard or modified ASTM tests to determine basic material properties on eight types of grout. The grouts were also used in tests that approximated the conditions in a deck panel system. Based on these tests, requirements for shrinkage, compressive strength, and flow were established for the grouts. It was more difficult to establish a test method and an acceptable performance level for adhesion, an important property for the strength and durability of the deck panel system. The second objective was to quantify the horizontal shear strength of the connection between the deck panel and the beam prestressed concrete beams. This portion of the research also investigated innovative methods of creating the connection. Push-off tests were conducted using several types of grout and a variety of connections. These tests were used to develop equations for the horizontal shear strength of the details. Two promising alternate connections, the hidden pocket detail and the shear stud detail, were tested for constructibility and strength. The final outcome of this study a set of recommendations for the design, detailing, and construction of the connection between full-depth precast deck panels and prestressed concrete I-beams. If designed and constructed properly, the deck panel system is an excellent option when rapid bridge deck construction or replacement is required.

A Systematic Investigation of Shear Connections Between Full-depth Precast Panels and Precast Prestressed Bridge Girders

A Systematic Investigation of Shear Connections Between Full-depth Precast Panels and Precast Prestressed Bridge Girders
Author: Robert Wayne Brey
Publisher:
Total Pages:
Release: 2010
Genre:
ISBN:

Full-depth precast panels are used in concrete bridges to provide several benefits such as faster construction, lower cost and reduced constructional hazard. However, one construction drawback is that connectors are required to transmit horizontal shear across the interface between the girder and deck. Shear connector performance is characterized by a series of experiments performed on part of a bridge system that mimics a full-depth precast deck on concrete girder with a pocket-connector-haunch system. Following initial breakaway of the adhesive bond within the haunch region, the specimens slide with frictional resistance provided by the clamping force of the anchor bolt. This leads to bolt yield with an observed sliding friction coefficient of 0.8 (+/- 20%) with lower values occurring at higher displacements. It is concluded that for a viable connector system to be developed a key feature is to have sufficient stirrups in the neighborhood of the anchor bolt to form a non-contact splice and to ensure the high pull-out force can be sustained without leading to premature beam failure. The successful implementation of a full-depth precast deck-panel system requires the use of a viable design methodology that properly accounts for system behavior. The design of a deck-haunch-girder system uses a truss modeling approach to design for the shear forces created by service loading. The truss model approach is considered more suitable for a concrete member due to the premise that the member will be substantially cracked at an ultimate limit state and that traditional beam theory does not account for the decreased ability of shear stresses to transfer across open cracks. Experimental results from Chapter II, such as the friction coefficient mu, are used along with a previously developed crack angle model to layout the geometry of the truss within a deck-panel span. Design solutions are presented utilizing the Rock Creek Bridge in Parker County, Texas as an example structure.

Design of Shear Connectors for Precast Concrete Decks in Concrete Girder Bridges

Design of Shear Connectors for Precast Concrete Decks in Concrete Girder Bridges
Author: Afshin Hatami
Publisher:
Total Pages: 292
Release: 2014
Genre: Bridges
ISBN: 9781321130065

Full-depth precast concrete deck systems have several advantages over traditional cast-in-place concrete decks. Higher concrete quality, accelerated construction, and reduced life-cycle cost are the main advantages. Full-depth precast concrete deck systems can be designed as composite or non-composite systems with the supporting girders. Composite systems are commonly used due to their superior structural performance and cost effectiveness. These systems require the use of shear connectors between the precast concrete deck panels and the supporting girders to transfer interface shear and achieve composite action. The use of discrete clustered shear connectors is highly preferred in order to simplify panel and girder fabrication and improve system constructability. However, existing code provisions for the design of shear connectors were developed for continuous small-diameter shear connectors and might not be adequate for the design of discrete clustered connectors especially when large diameter connectors are used.

Composite Steel and Concrete Structures: Fundamental Behaviour (Second Edition)

Composite Steel and Concrete Structures: Fundamental Behaviour (Second Edition)
Author: D.J. Oehlers
Publisher: Elsevier
Total Pages: 588
Release: 2013-10-22
Genre: Technology & Engineering
ISBN: 1483287718

This book deals with the analysis and behaviour of composite structural members that are made by joining a steel component to a concrete component. The emphasis of the book is to impart a fundamental understanding of how composite structures work, so engineers develop a feel for the behaviour of the structure, often missing when design is based solely by using codes of practice or by the direct application of prescribed equations. It is not the object to provide quick design procedures for composite members, as these are more than adequately covered by recourse to such aids as safe load tables. The subject should therefore be of interest to practising engineers, particularly if they are involved in the design of non-standard or unusual composite structures for buildings and bridges, or are involved in assessing, upgrading, strengthening or repairing existing composite structures. The fundamentals in composite construction are covered first, followed by more advanced topics that include: behaviour of mechanical and rib shear connectors; local buckling; beams with few shear connectors; moment redistribution and lateral-distortional buckling in continuous beams; longitudinal splitting; composite beams with service ducts; composite profiled beams and profiled slabs; composite columns; and the fatigue design and assessment of composite bridge beams.