Development of Bridge Load Testing Process for Load Evaluation, TR-445, 2003

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 are 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 steel-girder bridges with timber decks. In addition, a steel-girder bridge with a concrete deck previously tested and modeled by BDI was investigated for model verification purposes. The tests were performed by attaching strain transducers on the bridges at critical locations to measure strains resulting from truck loading positioned at various locations on the bridge. The field test results were used to develop and validate analytical rating models. Based on the experimental and analytical results, it was determined that bridge tests could be conducted relatively easy, that accurate models could be generated with the BDI software, and that the load ratings, in general, were greater than the ratings, obtained using the codified LFD Method (according to AASHTO Standard Specifications for Highway Bridges).

Field Testing of Integral Abutments, Interim Report, HR-399, 1998

Integral abutment bridges are constructed without an expansion joint in the superstructure of the bridge; therefore, the bridge girders, deck, abutment diaphragms, and abutments are monolithically constructed. The abutment piles in an integral abutment bridge are vertically orientated, and they are embedded into the pile cap. When this type of a bridge experiences thermal expansion or contraction, horizontal displacements are induced at the top of the abutment piles. The flexibility of the abutment piles eliminates the need to provide an expansion joint at the inside face to the abutments: Integral abutment bridge construction has been used in Iowa and other states for many years. This research is evaluating the performance of integral abutment bridges by investigating thermally induced displacements, strains, and temperatures in two Iowa bridges. Each bridge has a skewed alignment, contains five prestressed concrete girders that support a 30-ft wide roadway for three spans, and involves a water crossing. The bridges will be monitored for about two years. For each bridge, an instrumentation package includes measurement devices and hardware and software support systems. The measurement devices are displacement transducers, strain gages, and thermocouples. The hardware and software systems include a data-logger; multiplexers; directline telephone service and computer terminal modem; direct-line electrical power; lap-top computer; and an assortment of computer programs for monitoring, transmitting, and management of the data. Instrumentation has been installed on a bridge located in Guthrie County, and similar instrumentation is currently being installed on a bridge located in Story County. Preliminary test results for the bridge located in Guthrie County have revealed that temperature changes of the bridge deck and girders induce both longitudinal and transverse displacements of the abutments and significant flexural strains in the abutment piles. For an average temperature range of 73° F for the superstructure concrete in the bridge located in Guthrie County, the change in the bridge length was about 1 118 in. and the maximum, strong-axis, flexural-strain range for one of the abutment piles was about 400 micro-strains, which corresponds to a stress range of about 11,600 psi.

Synthesis of Nondestructive Testing Technologies for Geomaterial Applications, May 2005

Current monitoring techniques for determination of compaction of earthwork and asphalt generally involve destructive testing of the materials following placement. Advances in sensor technologies show significant promise for obtaining necessary information through nondestructive and remote techniques. To develop a better understanding of suitable and potential technologies, this study was undertaken to conduct a synthesis review of nondestructive testing technologies and perform preliminary evaluations of selected technologies to better understand their application to testing of geomaterials (soil fill, aggregate base, asphalt, etc.). This research resulted in a synthesis of potential technologies for compaction monitoring with a strong emphasis on moisture sensing. Techniques were reviewed and selectively evaluated for their potential to improve field quality control operations. Activities included an extensive review of commercially available moisture sensors, literature review, and evaluation of selected technologies. The technologies investigated in this study were dielectric, nuclear, near infrared spectroscopy, seismic, electromagnetic induction, and thermal. The primary disadvantage of all the methods is the small sample volume measured. In addition, all the methods possessed some sensitivity to non-moisture factors that affected the accuracy of the results. As the measurement volume increases, local variances are averaged out providing better accuracy. Most dielectric methods with the exception of ground penetrating radar have a very small measurement volume and are highly sensitive to variations in density, porosity, etc.

Facts about Iowa Law Enforcement Physical Standards for Pre-employment Testing, 2011

The Iowa Law Enforcement Academy Council, in recognizing the importance of physical fitness status for job performance, established this physical test regimen as a employment standard effective February 15, 1993. No person can be selected or appointed as a law enforcement officer without first successfully passing all of the elements of this test. (See 501 IAC 2.1, adopted pursuant to Section 80B.11(5), Code of Iowa.) Upon entry into the Academy every candidate will be given the same test as an assessment for training purposes and to ensure that each recruit can undergo the physical demands of the Academy without undue risk of injury, and with a level of fatigue tolerance to meet all Academy requirements. If at the time of entrance into the Academy an officer does not meet minimum standards, he or she will not be admitted. This pamphlet will provide information on the rationale, purpose, testing procedures, standards of performance and fitness activities to prepare for the fitness testing. It is intended to answer the basic questions pertaining to all aspects of the fitness testing process.

Electronic Construction Collaboration System – Phase III, December 2011

This phase of the electronic collaboration project involved two major efforts: 1) implementation of AEC Sync (formerly known as Attolist), a web-based project management system (WPMS), on the Broadway Viaduct Bridge Project and the Iowa Falls Arch Bridge Project and 2) development of a web-based project management system for bridge and highway construction projects with less than $10 million in contract value. During the previous phase of this project (fiscal year 2010), the research team helped with the implementation process for AEC Sync and collected feedback from the Broadway Viaduct project team members before the start of the project. During the 2011 fiscal year, the research team collected the post-project surveys from the Broadway Viaduct project members and compared them to the pre-project survey results. The results of the AEC Sync implementation on the Broadway project were positive. The project members were satisfied with the performance of the AEC Sync software and how it facilitated document management and its transparency. In addition, the research team distributed, collected, and analyzed the pre-project surveys for the Iowa Falls Arch Bridge Project. The implementation of AEC Sync for the Iowa Falls Arch Bridge Project appears to also be positive, based on the pre-project surveys. The fourth phase of this electronic collaboration project involves the identification and implementation of a WPMS solution for smaller bridge and highway projects. The workflow for the shop drawing approval process for sign truss projects was documented and used to identify possible WPMS solutions. After testing and evaluating several WPMS solutions, Microsoft SharePoint Foundation’s site pages were selected to be pilot-tested on sign truss projects. Due to the limitation on the SharePoint license that the Iowa Department of Transportation (DOT) has, a file transfer protocol (FTP) site will be developed alongside this site to allow contractors to upload shop drawings to the Iowa DOT. The SharePoint site pages are expected to be ready for implementation during the 2012 calendar year.

A Guide to Workforce Drug Testing in Iowa, October 13, 2010

The purpose of the State of Iowa’s drug testing law—Iowa Code Section 730.5 (& Administrative Code Section 641)—is to enhance worker safety, by creating workplaces that are free of drugs and substance abuse. One tool available to private sector employers is drug testing (inclusive of alcohol testing), that often is coupled with educational efforts as part of a comprehensive drug-free workplace program. Each employer must first decide if drug and/or alcohol testing is appropriate for them. Under Iowa law, workplace drug or alcohol testing is optional for private sector employers. Federal laws or regulations governing drug or alcohol testing supersede state law in Iowa.

Results from the Testing of Adulterated Anhydrous Ammonia Provided by the State of Iowa's Office of Drug Control Policy, March 15, 2004

The report of adulterated anhydrous ammonia did not completely prevent the manufacture of methamphetamine. The amount of the methamphetamine manufactured using the adulterated ammonia was consistently very low. Although clandestine laboratory "field-like" reaction conditions were mimicked for purposes of these tests it should be noted that no attempts were made to distill the adulterated anhydrous ammonia.

A Guide to Workplace Drug Testing in Iowa, October 13, 2010

The purpose of the State of Iowa’s drug testing law—Iowa Code Section 730.5 (& Administrative Code Section 641)—is to enhance worker safety, by creating workplaces that are free of drugs and substance abuse. One tool available to private sector employers is drug testing (inclusive of alcohol testing), that often is coupled with educational efforts as part of a comprehensive drug-free workplace program. Each employer must first decide if drug and/or alcohol testing is appropriate for them. Under Iowa law, workplace drug or alcohol testing is optional for private sector employers. Federal laws or regulations governing drug or alcohol testing supersede state law in Iowa.

Task 4: Testing Iowa Portland Cement Concrete Mixtures for the AASHTO Mechanistic-Empirical Pavement Design Procedure, May 2008

The present research project was designed to identify the typical Iowa material input values that are required by the Mechanistic-Empirical Pavement Design Guide (MEPDG) for the Level 3 concrete pavement design. It was also designed to investigate the existing equations that might be used to predict Iowa pavement concrete for the Level 2 pavement design. In this project, over 20,000 data were collected from the Iowa Department of Transportation (DOT) and other sources. These data, most of which were concrete compressive strength, slump, air content, and unit weight data, were synthesized and their statistical parameters (such as the mean values and standard variations) were analyzed. Based on the analyses, the typical input values of Iowa pavement concrete, such as 28-day compressive strength (f’c), splitting tensile strength (fsp), elastic modulus (Ec), and modulus of rupture (MOR), were evaluated. The study indicates that the 28-day MOR of Iowa concrete is 646 + 51 psi, very close to the MEPDG default value (650 psi). The 28-day Ec of Iowa concrete (based only on two available data of the Iowa Curling and Warping project) is 4.82 + 0.28x106 psi, which is quite different from the MEPDG default value (3.93 x106 psi); therefore, the researchers recommend re-evaluating after more Iowa test data become available. The drying shrinkage (εc) of a typical Iowa concrete (C-3WR-C20 mix) was tested at Concrete Technology Laboratory (CTL). The test results show that the ultimate shrinkage of the concrete is about 454 microstrain and the time for the concrete to reach 50% of ultimate shrinkage is at 32 days; both of these values are very close to the MEPDG default values. The comparison of the Iowa test data and the MEPDG default values, as well as the recommendations on the input values to be used in MEPDG for Iowa PCC pavement design, are summarized in Table 20 of this report. The available equations for predicting the above-mentioned concrete properties were also assembled. The validity of these equations for Iowa concrete materials was examined. Multiple-parameters nonlinear regression analyses, along with the artificial neural network (ANN) method, were employed to investigate the relationships among Iowa concrete material properties and to modify the existing equations so as to be suitable for Iowa concrete materials. However, due to lack of necessary data sets, the relationships between Iowa concrete properties were established based on the limited data from CP Tech Center’s projects and ISU classes only. The researchers suggest that the resulting relationships be used by Iowa pavement design engineers as references only. The present study furthermore indicates that appropriately documenting concrete properties, including flexural strength, elastic modulus, and information on concrete mix design, is essential for updating the typical Iowa material input values and providing rational prediction equations for concrete pavement design in the future.

Development of a Computer Controlled Underbody Plow: TR412, Final Report, January 2006

Underbody plows can be very useful tools in winter maintenance, especially when compacted snow or hard ice must be removed from the roadway. By the application of significant down-force, and the use of an appropriate cutting edge angle, compacted snow and ice can be removed very effectively by such plows, with much greater efficiency than any other tool under those circumstances. However, the successful operation of an underbody plow requires considerable skill. If too little down pressure is applied to the plow, then it will not cut the ice or compacted snow. However, if too much force is applied, then either the cutting edge may gouge the road surface, causing significant damage often to both the road surface and the plow, or the plow may ride up on the cutting edge so that it is no longer controllable by the operator. Spinning of the truck in such situations is easily accomplished. Further, excessive down force will result in rapid wear of the cutting edge. Given this need for a high level of operator skill, the operation of an underbody plow is a candidate for automation. In order to successfully automate the operation of an underbody plow, a control system must be developed that follows a set of rules that represent appropriate operation of such a plow. These rules have been developed, based upon earlier work in which operational underbody plows were instrumented to determine the loading upon them (both vertical and horizontal) and the angle at which the blade was operating.These rules have been successfully coded into two different computer programs, both using the MatLab® software. In the first program, various load and angle inputs are analyzed to determine when, whether, and how they violate the rules of operation. This program is essentially deterministic in nature. In the second program, the Simulink® package in the MatLab® software system was used to implement these rules using fuzzy logic. Fuzzy logic essentially replaces a fixed and constant rule with one that varies in such a way as to improve operational control. The development of the fuzzy logic in this simulation was achieved simply by using appropriate routines in the computer software, rather than being developed directly. The results of the computer testing and simulation indicate that a fully automated, computer controlled underbody plow is indeed possible. The issue of whether the next steps toward full automation should be taken (and by whom) has also been considered, and the possibility of some sort of joint venture between a Department of Transportation and a vendor has been suggested.

Testing Guide for Implementing Concrete Paving Quality Control Procedures, March 2008

Construction of portland cement concrete pavements is a complex process. A small fraction of the concrete pavements constructed in the United States over the last few decades have either failed prematurely or exhibited moderate to severe distress. In an effort to prevent future premature failures, 17 state transportation agencies pooled their resources, and a pooled fund research project, Material and Construction Optimization for Prevention of Premature Pavement Distress in PCC Pavements, was undertaken in 2003. Its purpose was to evaluate existing quality control tests, and then select and advance the state-of-the-practice of those tests most useful for optimizing concrete pavements during mix design, mix verification, and construction. This testing guide is one product of that project. The guide provides three recommended testing schemes (Levels A, B, and C, depending on a pavement’s design life and traffic volumes, etc.) that balance the costs of testing with the risk of failure for various project types. The recommended tests are all part of a comprehensive suite of tests described in detail in this guide.

Precast Concrete Elements for Accelerated Bridge Construction Final Report, Volume 1-1. Laboratory Testing of Precast Substructure Components: Boone County Bridge, January 2009

In July 2006, construction began on an accelerated bridge project in Boone County, Iowa that was composed of precast substructure elements and an innovative, precast deck panel system. The superstructure system consisted of full-depth deck panels that were prestressed in the transverse direction, and after installation on the prestressed concrete girders, post-tensioned in the longitudinal direction. Prior to construction, laboratory tests were completed on the precast abutment and pier cap elements. The substructure testing was to determine the punching shear strength of the elements. Post-tensioning testing and verification of the precast deck system was performed in the field. The forces in the tendons provided by the contractor were verified and losses due to the post-tensioning operation were measured. The stress (strain) distribution in the deck panels due to the post-tensioning was also measured and analyzed. The entire construction process for this bridge system was documented. Representatives from the Boone County Engineers Office, the prime contractor, precast fabricator, and researchers from Iowa State University provided feedback and suggestions for improving the constructability of this design.

Precast Concrete Elements for Accelerated Bridge Construction Final Report Volume 2. Laboratory Testing, Field Testing, and Evaluation of a Precast Concrete Bridge: Madison County Bridge, January 2009

The importance of rapid construction technologies has been recognized by the Federal Highway Administration (FHWA) and the Iowa DOT Office of Bridges and Structures. Recognizing this a two-lane single-span precast box girder bridge was constructed in 2007 over a stream. The bridge’s precast elements included precast cap beams and precast box girders. Precast element fabrication and bridge construction were observed, two precast box girders were tested in the laboratory, and the completed bridge was field tested in 2007 and 2008.

Precast Concrete Elements for Accelerated Bridge Construction Final Report Volume 3. Laboratory Testing, Field Testing, and Evaluation of a Precast Concrete Bridge: Black Hawk County,v January 2009

The importance of rapid construction technologies has been recognized by the Federal Highway Administration (FHWA) and the Iowa DOT Office of Bridges and Structures. Black Hawk County (BHC) has developed a precast modified beam-in-slab bridge (PMBISB) system for use with accelerated construction. A typical PMBISB is comprised of five to six precast MBISB panels and is used on low volume roads, on short spans, and is installed and fabricated by county forces. Precast abutment caps and a precast abutment backwall were also developed by BHC for use with the PMBISB. The objective of the research was to gain knowledge of the global behavior of the bridge system in the field, to quantify the strength and behavior of the individual precast components, and to develop a more time efficient panel-to-panel field connection. Precast components tested in the laboratory include two precast abutment caps, three different types of deck panel connections, and a precast abutment backwall. The abutment caps and backwall were tested for behavior and strength. The three panel-to-panel connections were tested in the lab for strength and were evaluated based on cost and constructability. Two PMBISB were tested in the field to determine stresses, lateral distribution characteristics, and overall global behavior.

Development of LRFD Procedures for Bridge Pile Foundations in Iowa: Volume II: Field Testing of Steel Piles in Clay, Sand, and Mixed Soils and Data Analysis, September 2011

In response to the mandate on Load and Resistance Factor Design (LRFD) implementations by the Federal Highway Administration (FHWA) on all new bridge projects initiated after October 1, 2007, the Iowa Highway Research Board (IHRB) sponsored these research projects to develop regional LRFD recommendations. The LRFD development was performed using the Iowa Department of Transportation (DOT) Pile Load Test database (PILOT). To increase the data points for LRFD development, develop LRFD recommendations for dynamic methods, and validate the results ofLRFD calibration, 10 full-scale field tests on the most commonly used steel H-piles (e.g., HP 10 x 42) were conducted throughout Iowa. Detailed in situ soil investigations were carried out, push-in pressure cells were installed, and laboratory soil tests were performed. Pile responses during driving, at the end of driving (EOD), and at re-strikes were monitored using the Pile Driving Analyzer (PDA), following with the CAse Pile Wave Analysis Program (CAPWAP) analysis. The hammer blow counts were recorded for Wave Equation Analysis Program (WEAP) and dynamic formulas. Static load tests (SLTs) were performed and the pile capacities were determined based on the Davisson’s criteria. The extensive experimental research studies generated important data for analytical and computational investigations. The SLT measured loaddisplacements were compared with the simulated results obtained using a model of the TZPILE program and using the modified borehole shear test method. Two analytical pile setup quantification methods, in terms of soil properties, were developed and validated. A new calibration procedure was developed to incorporate pile setup into LRFD.