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  • Development of Bridge Load Testing for Load Evaluation (TR-445)
    445 BDI Autoclicker in use during a load test Researcher s Principal investigators Terry Wipf 515 294 6979 tjwipf iastate edu Co principal investigators Doug Wood 515 294 3768 dwoody iastate edu Wayne Klaiber 515 294 8763 klaiber iastate edu Project status Completed Start date 05 22 00 End date 08 31 02 Publications Report Development of Bridge Load Testing for Load Evaluation TR 445 2 9 MB pdf April 2003 Sponsor s partner s Sponsor s Iowa Department of Transportation Iowa Highway Research Board About the research Abstract Recent reports indicate that of the over 25 000 bridges in Iowa slightly over 7 000 29 are either structurally deficient or functionally obsolete While many of these bridges may be strengthened or rehabilitated some simply need to be replaced Before implementing one of these options one should consider performing a diagnostic load test on the structure to more accurately assess its load carrying capacity Frequently diagnostic load tests reveal strength and serviceability characteristics that exceed the predicted codified parameters Usually codified parameters are very conservative in predicting lateral load distribution characteristics and the influence of other structural attributes As a result the predicted rating factors are typically conservative In cases where theoretical calculations show a structural deficiency it may be very beneficial to apply a tool that utilizes a more accurate theoretical model which incorporates field test data At a minimum this approach results in more accurate load ratings and many times results in increased rating factors Bridge Diagnostics Inc BDI developed hardware and software that is specially designed for performing bridge ratings based on data obtained from physical testing To evaluate the BDI system the research team performed diagnostic load tests on seven typical bridge structures three steel girder bridges with concrete decks two concrete slab bridges and two

    Original URL path: http://www.ctre.iastate.edu/research/detail.cfm?projectID=455 (2015-11-09)
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  • Retrofit Methods of Distortion Cracking Problems in Plate Girder Bridges (TR-436)
    the diaphragm connections This fatigue prone web gap area is typically located in negative moment regions of the girders where the diaphragm stiffener is not attached to the top flange In the past the Iowa Department of Transportation has attempted to stop fatigue crack propagation in these steel girder bridges by drilling holes at the crack tips Other nondestructive retrofits have been tried in a particular case on a two girder bridge with floor beams angles were bolted between the stiffener and top flange The bolted angle retrofit has failed in the past and may not be a viable solution for diaphragm bridges The drilled hole retrofit is often only a temporary solution so a more permanent and effective retrofit is required A new field retrofit has been developed that involves loosening the bolts in the connection between the diaphragm and the girders Research on the retrofit has been initiated however no long term studies of the effects of bolt loosening have been performed The intent of this research is to study the short term effects of the bolt loosening retrofit on I beam and channel diaphragm bridges The research also addressed the development of a continuous remote monitoring system to investigate the bolt loosening retrofit on an X type diaphragm bridge over a number of months ensuring that the measured strain and displacement reductions are not affected by time and continuous traffic loading on the bridge The testing for the first three investigations is based on instrumentation of web gaps in a negative moment region on Iowa Department of Transportation bridges with I beam channel and X type diaphragms One bridge of each type was instrumented with strain gages and deflection transducers Field tests using loaded trucks of known weight and configuration were conducted on the bridges with the

    Original URL path: http://www.ctre.iastate.edu/research/detail.cfm?projectID=301 (2015-11-09)
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  • Traffic Control Strategies in Work Zones with Edge Drop-Offs
    States Smart Work Zone Deployment Initiative Year 4 Researcher s Principal investigator Ed Kannel 515 294 2861 ekannel iastate edu Co principal investigator Tom McDonald Project status Completed Start date 06 01 97 End date 08 31 02 Publications Report Traffic Control Strategies in Work Zones with Edge Drop Offs 887KB pdf August 2002 Sponsor s partner s Sponsor s Iowa Department of Transportation About the research Abstract Pavement and shoulder edge drop offs commonly occur in work zones as the result of overlays pavement replacement or shoulder construction The depth of these elevation differentials can vary from approximately one inch when a flexible pavement overlay is applied to several feet where major reconstruction is undertaken The potential hazards associated with pavement edge differentials depend on several factors including depth of the drop off shape of the pavement edge distance from traveled way vehicle speed traffic mix volume and other factors This research was undertaken to review current practices in other states for temporary traffic control strategies addressing lane edge differentials and to analyze crash data and resultant litigation related to edge drop offs An objective was to identify cost effective practices that would minimize the potential for and impacts of edge drop crashes in work zones Considerable variation in addressing temporary traffic control in work zones with edge drop off exposure was found among the states surveyed Some states base traffic control plans on only one factor the depth of the drop off Other states consider additional issues such as the expected duration of exposure posted speed limit average annual daily traffic and the lateral distance from the traveled way to the drop off All of the states surveyed indicated that edge drop off treatment is initiated before a depth of three inches is encountered The elevation differential warranting

    Original URL path: http://www.ctre.iastate.edu/research/detail.cfm?projectID=255 (2015-11-09)
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  • Synthesis of Dowel Bar Research (HR-1080)
    FAX 515 294 0467 Website www ctre iastate edu Copyright 1996 2009 Iowa State University All rights reserved Synthesis of Dowel Bar Research HR 1080 Researcher s Principal investigators Max Porter 515 294 7456 mporter iastate edu Project status Completed Start date 07 01 01 End date 08 15 02 Publications Report Synthesis of Dowel Bar Research HR 1080 1 02MB pdf August 2002 Sponsor s partner s Sponsor s

    Original URL path: http://www.ctre.iastate.edu/research/detail.cfm?projectID=476 (2015-11-09)
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  • Iowa DOT Linear Referencing System: Preliminary Linear Data Creation
    State University center administered by the Institute for Transportation Address 2711 S Loop Drive Suite 4700 Ames IA 50010 8664 Phone 515 294 8103 FAX 515 294 0467 Website www ctre iastate edu Copyright 1996 2009 Iowa State University All rights reserved Iowa DOT Linear Referencing System Preliminary Linear Data Creation Researcher s Principal investigators Reginald Souleyrette Co principal investigators Zachary Hans 515 294 2329 zhans iastate edu Project status

    Original URL path: http://www.ctre.iastate.edu/research/detail.cfm?projectID=532 (2015-11-09)
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  • Development of a GIS-based Crash Location Tool - FY02 Location Tool Implementation and Agency Support
    center administered by the Institute for Transportation Address 2711 S Loop Drive Suite 4700 Ames IA 50010 8664 Phone 515 294 8103 FAX 515 294 0467 Website www ctre iastate edu Copyright 1996 2009 Iowa State University All rights reserved Development of a GIS based Crash Location Tool FY02 Location Tool Implementation and Agency Support Researcher s Co principal investigators Dan Gieseman Project status Completed Start date 07 01 01

    Original URL path: http://www.ctre.iastate.edu/research/detail.cfm?projectID=472 (2015-11-09)
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  • Evaluation of Composite Pavement Unbonded Overlays, Phases I and II (TR-478, Proj. 2)
    Evaluation of Composite Pavement Unbonded Overlays Phases I and II TR 478 Proj 2 Researcher s Principal investigators James K Cable Cable Concrete Consultation Student researcher Michael Anthony Project status Completed Start date 07 01 01 End date 06 30 02 Publications Report Evaluation of Composite Pavement Unbonded Overlays Phases I and II TR 478 Proj 2 2 1 mb pdf April 2003 Sponsor s partner s Sponsor s Federal Highway Administration Iowa Highway Research Board About the research Abstract In recent years thin whitetopping has evolved as a viable rehabilitation technique for deteriorated asphalt cement concrete ACC pavements Numerous projects have been constructed and tested these projects allow researchers to identify the important elements contributing to the projects successes These elements include surface preparation overlay thickness synthetic fiber reinforcement usage joint spacing and joint sealing Although the main factors affecting thin whitetopping performance have been identified by previous research questions still existed as to the optimum design incorporating these variables The objective of this research is to investigate the interaction between these variables over time Laboratory testing and field testing were planned in order to accomplish the research objective Laboratory testing involved shear testing of the bond between the

    Original URL path: http://www.ctre.iastate.edu/research/detail.cfm?projectID=497 (2015-11-09)
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  • Evaluation of Rammed Aggregate Piers for Highway Applications in Iowa Soils (TR-443)
    Jun 2005 Sponsor s partner s Sponsor s Geopier Foundation Company Iowa Department of Transportation Iowa Highway Research Board About the research Abstract This report describes a study to evaluate Geopier trademarked name soil reinforcement technology in transportation construction Three projects requiring settlement control were chosen for evaluation an embankment foundation a box culvert and a bridge approach fill For each project construction observations in situ soil testing laboratory material characterization and performance monitoring were carried out For the embankment foundation project Geopier elements were installed within and around an abutment footprint for the new I 35 overpass at the US Highway 5 Interstate 35 interchange in Des Moines Iowa Although the main focus of this investigation was to evaluate embankment foundation reinforcement using Geopier elements a stone column reinforced soil provided an opportunity to compare systems In situ testing included cone penetration tests CPTs pressuremeter tests PMTs Ko stepped blade tests and borehole shear tests BSTs as well as laboratory material testing Comparative stiffness and densities of Geopier elements and stone columns were evaluated based on full scale modulus load tests and standard penetration tests Vibrating wire settlement cells and total stress cells were installed to monitor settlement and stress concentration on the reinforcing elements and matrix soil Settlement plates were also monitored by conventional optical survey methods Results show that the Geopier system and the stone columns performed their intended functions The second project involved settlement monitoring of a 4 2 m wide x 3 6 m high x 50 m long box culvert constructed beneath a bridge on Iowa Highway 191 south of Neola Iowa Geopier elements were installed to reduce total and differential settlement while ensuring the stability of the existing bridge pier foundations Benefits of the box culvert and embankment fill included 1 ease of

    Original URL path: http://www.ctre.iastate.edu/research/detail.cfm?projectID=254 (2015-11-09)
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