5 resultados para adhesive factor
em Iowa Publications Online (IPO) - State Library, State of Iowa (Iowa), United States
Resumo:
The joint between two lanes of asphalt pavement is often the first area of a roadway which shows signs of deterioration and requires maintenance. As the final lift of hot asphalt is being placed in a construction project, it is being forced p against the adjoining lane of cold asphalt, forming the longitudinal joint. The mating of the two lanes, to form a high quality seal, is often not fully successful and later results in premature stripping or raveling as water enters the unsealed joint. The application of a hot poured rubberized asphaltic joint sealant along the joint face in the final stage of construction should help to form a watertight joint seal. A new product, especially formulated for the longitudinal joint in asphalt pavements was proposed to improve joint sealing. The following describes the experimental application of the new product, Crafco, PN 34524.
Resumo:
The Federal Highway Administration (FHWA) mandated utilizing the Load and Resistance Factor Design (LRFD) approach for all new bridges initiated in the United States after October 1, 2007. To achieve part of this goal, a database for Drilled Shaft Foundation Testing (DSHAFT) was developed and reported on by Garder, Ng, Sritharan, and Roling in 2012. DSHAFT is aimed at assimilating high-quality drilled shaft test data from Iowa and the surrounding regions. DSHAFT is currently housed on a project website (http://srg.cce.iastate.edu/dshaft) and contains data for 41 drilled shaft tests. The objective of this research was to utilize the DSHAFT database and develop a regional LRFD procedure for drilled shafts in Iowa with preliminary resistance factors using a probability-based reliability theory. This was done by examining current design and construction practices used by the Iowa Department of Transportation (DOT) as well as recommendations given in the American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications and the FHWA drilled shaft guidelines. Various analytical methods were used to estimate side resistance and end bearing of drilled shafts in clay, sand, intermediate geomaterial (IGM), and rock. Since most of the load test results obtained from O-cell do not pass the 1-in. top displacement criterion used by the Iowa DOT and the 5% of shaft diameter for top displacement criterion recommended by AASHTO, three improved procedures are proposed to generate and extend equivalent top load-displacement curves that enable the quantification of measured resistances corresponding to the displacement criteria. Using the estimated and measured resistances, regional resistance factors were calibrated following the AASHTO LRFD framework and adjusted to resolve any anomalies observed among the factors. To illustrate the potential and successful use of drilled shafts in Iowa, the design procedures of drilled shaft foundations were demonstrated and the advantages of drilled shafts over driven piles were addressed in two case studies.
Resumo:
The Iowa Department of Transportation (IaDOT) was interested in investigating the use of epoxy adhesive anchorages for the attachment of posts used in the BR27C combination bridge rail system. Alternative anchorage concepts were developed using a modified version of the ACI 318-11 procedures for embedded anchor design. Four design concepts were developed for review by IaDOT, including: (1) a four-bolt square anchorage, (2) a four-bolt spread anchorage, (3) a twobolt centered anchorage, and (4) a two-bolt offset anchorage. IaDOT representatives selected the four-bolt spread anchorage and the two-bolt offset anchorage as the preferred designs for evaluation. In addition to these two proposed configurations, IaDOT also requested that the researchers evaluate a third option that had been previously installed on the US-20 bridge near Hardin, IA. The proposed alternative anchorages and the original cast-in-place anchorage for the BR27C combination bridge rail were evaluated through dynamic component testing. The test of the original cast-in-place anchorage was used a baseline for comparison with the alternative designs. Test no. IBP-1 of the original cast-in-place anchorage developed a peak load of 22.9 kips (101.9 kN) at a deflection of 1.5 in. (38 mm). All three of the tested alternative anchorages provided greater load capacity than the original cast-in-place design and were deemed acceptable surrogates. Of the three alternative designs, the two-bolt offset design was deemed the best option.
Resumo:
The Iowa Behavioral Risk Factor Surveillance System (BRFSS) is an ongoing telephone survey. It is financially and technically supported by the CDC with further financial support from public and private sources. The BRFSS is designed to collect information on the health conditions, health-related behaviors, attitudes, and awareness of residents age 18 and over. It also monitors the prevalence of these indicators over time. The indicators surveyed are major contributors to illness, disability, and premature death. This report focuses on the data collected during calendar year 2013. Some of the health-related issues discussed are general health status, health care access, cancer screening, tobacco use, alcohol consumption, body weight, physical activity, oral health, diabetes, respiratory conditions, immunizations, and HIV/AIDS awareness.
Resumo:
The Iowa Behavioral Risk Factor Surveillance System (BRFSS) is an ongoing telephone survey. It is financially and technically supported by the CDC with further financial support from public and private sources. The BRFSS is designed to collect information on the health conditions, health-related behaviors, attitudes, and awareness of residents age 18 and over. It also monitors the prevalence of these indicators over time. The indicators surveyed are major contributors to illness, disability, and premature death. This report focuses on the data collected during calendar year 2013. Some of the health-related issues discussed are general health status, health care access, cancer screening, tobacco use, alcohol consumption, body weight, physical activity, oral health, diabetes, respiratory conditions, immunizations, and HIV/AIDS awareness.