As cold-formed steel decks are used in virtually every steel-framed structure for
composite slab systems, efforts to develop more efficient composite floor systems continues.
Efficient composite floor systems can be obtained by optimally utilizing the materials, which
includes the possibility of developing long span composite slab systems. For this purpose, new
deck profiles that can have a longer span and better interaction with the concrete slab are
investigated.
Two new mechanical based methods for predicting composite slab strength and behavior
are introduced. They are referred to as the iterative and direct methods. These methods, which
accurately account for the contribution of parameters affecting the composite action, are used to
predict the strength and behavior of composite slabs. Application of the methods in the
analytical and experimental study of strength and behavior of composite slabs in general reveals
that more accurate predictions are obtained by these methods compared to those of a modified
version of the Steel Deck Institute method (SDI-M). A nonlinear finite element model is also
developed to provide additional reference. These methods, which are supported by elemental
tests of shear bond and end anchorages, offer an alternative solution to performing a large
number of full-scale tests as required for the traditional m-k method. Results from 27 composite
slab tests are compared with the analytical methods
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An Analysis of Skewed Bridge/Vehicle Interaction Using the Grillage Method
Author: H. Zeng, J. Kuehn, J. Sun, H. Stalford | Size: 49 KB | Format:PDF | Quality:Original preprint | Publisher: H. Zeng, J. Kuehn, J. Sun, H. Stalford | pages: 6
The 1998 Bridge Inventory classified approximately 68,000 of the 280,000
American highway bridges as substandard. One way to extend the useful service life of a
bridge is to reduce peak vehicle loads. Field tests conducted at Walnut Creek Bridge on
Interstate 35 near Purcell, Oklahoma revealed that it is common for vehicles to exert peak
dynamic loads 1.3-1.7 times their static weights on the bridge. The focus of this work is
to model the dynamic interaction between vehicles and the bridge to facilitate the
development of strategies aimed at reducing dynamic loads applied to the bridge.
Walnut Creek Bridge is a two-lane, four-span, continuous steel girder bridge with a
reinforced concrete deck. The bridge structure is modeled as an assembly of grillage
members, consisting of longitudinal and transverse torsion beams. The finite element
model includes 205 nodes and 425 elements. The vehicle used in the analysis is a
36,000kg tractor-trailer, which is the heaviest vehicle allowed on this bridge without a
permit. The vehicle model is a 7 degree-of-freedom planar representation that accounts
for both the heave and pitch. The equations of motion of the vehicle and the bridge are
treated as two subsystems and are solved separately using the fourth order Runge-Kutta
integration method in state space. The compatibility equations at the interface between
the vehicle tires and bridge deck are satisfied by an iterative procedure.
The simulation results are compared to experimental results obtained by using a
tractor-trailer for both quasi-static and dynamic tests. A response of a typical point of the
bridge has a peak error of 8.2% and an RMS error of 12.4% for the quasi-static case, and
a 17.6% peak error and a 24.5% RMS error for the dynamic case, respectively. The close
agreement between the simulations and experiments enables a study of the influence of
various parameters which contribute to the response of the interacted system.
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Dealing with a wide range of non-metallic materials, this book opens up possibilities of lighter, more durable structures. With contributions from leading international researchers and design engineers, it provides a complete overview of current knowledge on the subject.
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This reviews the progress made worldwide in the use of fibre reinforced polymers as structural components in bridges until the end of the year 2000. Due to their advantageous material properties such as high specific strength, a large tolerance for frost and de-icing salts and, furthermore, short installation times with minimum traffic interference, fibre reinforced polymers have matured to become valuable alternative building materials for bridge structures. Today, fibre reinforced polymers are manufactured industrially to semi-finished products and complete structural components, which can be easily and quickly installed or erected on site
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Steel Corrosion in Concrete: Fundamentals and Civil Engineering Practice
Author: Arnon Bentur, Sidney Diamond, Neal Steve Berke | Size: 3.05 MB | Format:HTML | Quality:Unspecified | Publisher: Taylor & Francis | Year: 1997 | pages: 201 | ISBN: 9780203974643
Poor durability of concrete is a major cause of problems in modern building and civil engineering structures in all countries: the annual cost of investigating and repairing deteriorating reinforced concrete structures runs into many millions of pounds. This book explains the fundamentals of the corrosion of steel in concrete. It is comprehensive and provides a basis for the practising engineer to design concrete structures which avoid the problem using modern concepts and specifications. A limited discussion of corrosion measurement and repairs is also provided.
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As a desktop companion for project managers and engineers, contract administrators, cost scheduling engineers and others engaged in the oil and gas industry, pipeline and petrochemical construction this book covers the entire contract process, including: Efficient preparation of quotation requests as bid packages Examples for suitable contract formats Evaluation of bids Qualification of delay and disruption costs Contract closeout procedures Invoicing, progress payments and work break down structures Just to name a few topics.
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The acrosswind response of isolated reinfe~c~d concrete chimneys of circular
cross-section is studied using wind tunnel tests, full-scale measureme,~ts and
response predictions based on semi-empirical methods. Three chimneys with available
full-scale response observations were selected for this study to compare their
measured and predicted responses. The wind tunnel experiments involved measurements
of unsteady aerodynamic loads on rigid models of circular cross-section and
aeroelastic response of scale models of full-scale chimenys. Tests were conducted
initially on smooth surface models, which were repeated with artificially roughened
surface. Attachment of discrete two dimensional surface roughness helps to simulate
artificially flow field features past a cylinder that represent the characteristics of high
Reynolds number flows. Utilizing this roughness configuration permits response
prediction of chimneys in boundary layer wind tunnels with a good agreement with
the observed full-scale response.
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BUCKLING OF ABOVEGROUND STORAGE TANKS WITH CONICAL ROOF
Author: Luis A. Godoy and Julio C. Mendez-Degró | Size: 256 KB | Format:PDF | Quality:Original preprint | Publisher: Luis A. Godoy and Julio C. Mendez-Degró | pages: 8
The buckling of aboveground circular steel tanks with conical roof is considered in this paper. The
specific source of loads investigated is wind action during hurricane storms in the Caribbean islands.
The structure is modeled using a finite element discretization with the computer package ALGOR.
Bifurcation buckling of the shell is computed for a given static wind pressure distribution. Then the
bifurcation loads and buckling modes are compared with the evidence of real tanks that failed during
hurricane Georges in Puerto Rico in 1998. Several pressure distributions are assumed for the roof of the
tank, and it is shown that the results are highly sensitive to the choice of pressures.
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This report presents results from an investigation of the structural behaviour of a 90 m high steel chimney equipped with a mechanical damper at the top. Due to a mistake in installing the chimney the damper was not active in the first period of service life, causing large oscillations of the structure and fatigue cracks to occur within a few months of service. Because of this an extensive investigation was started to rectify the action of the damper, repair the steel structure and to monitor the behaviour of the structure adopting a fail-safe principle. Data from four years of continuous measurements are presented in the report. VEAB of Växjö, Sweden is owner of the chimney, being part of a delivery of an electrostatic precipitator of the Sandvik II biomass power plant at Växjö. ABB Fläkt Industri AB of Växjö was contractor for the electrostatic precipitator including the chimney (activities of the company later subdivided between Alstom Power Sweden AB and ABB). The chimney was fabricated and erected by the subcontractor VL Staal A/S of Esbjerg, Denmark.
The authors are indebted to all parties involved for making it possible to present the results in this form. Special thanks are due to Mr Ulf Johnson of VEAB, Mr Lars Palmqvist of ABB Automation Systems AB, Mr Stig Magnell of Dryco AB, Messrs Rolf Snygg and Thomas Väärälä of Alstom Power Sweden AB, and Mr Stig Pedersen of VL Staal A/S.
The investigation presented in this report was initiated by VEAB, for which the second author acted as a consultant. The compilation of data and preparation of most parts of this report were made by the first author. The second author has acted mainly as advisor for the investigation.
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Wind-induced pressures acting on the Wind Engineering Research Field Laboratory
(WERFL) of Texas Tech University are integrated over each surface to obtain three
forces and moments at the base of the building along the three principal axes with its
origin at the geometric center of the building. Mean and fluctuating pressure
distributions around the WERFL building are investigated, and the pressure
distributions producing maximum fluctuating along-wind loading, across-wind
loading, and torsional moment are studied, and the correlation between these forces is
studied, a method to investigate the load combination of these forces is proposed.
WERFL building is also used for estimation of wind loading effects and
corresponding gust response factors and background factors, and a wind tunnel model
of Tokyo Polytechnic University is also utilized. The gust factors and back ground
factors of responses of these two buildings under wind loading are calculated
respectively. The responses calculated by pressure time histories are compared to
those calculated by applying ASCE7-05. Methods to investigate universal equivalent
static wind load are applied to both buildings. Several equivalent static wind loading
(ESWL) methods are compared, and the universal ESWL method is applied to
WERFL building and another modified universal ESWL method is also utilized for
WERFL building.
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