Reinforced concrete (RC) column-footing substructures are widely used to support bridges along critical transportation corridors in Oregon. Those built prior to 1971 were typically designed to resist only gravity loads. Therefore, they are vulnerable to damage or collapse during strong ground shaking. To prevent collapse, seismic retrofits have been developed...
Scour is the main cause of bridge failures in the United States. Bridge failures raise a hazard to the safety of the traveling public as well as the massive economic consequences due to the high cost of constructing a new or a replacement bridge. The Oregon Department of Transportation (ODOT)...
As ecoroofs have become more widespread throughout the U.S., it has become increasingly important to understand their structural behavior. The purpose of this research was to investigate the load effects exerted on a roof structure with an ecoroof during rain events and the subsequent drainage period, with the intention of...
In the first quarter of the twentieth century, iron was commonly used to provide tensile resistance for preservation and restoration of historical buildings. A major factor contributing to increasing the deterioration and degradation of historic structures is corrosion of ferrous materials. One approach to avoid long-term degradation of iron and...
Ecoroofs have become more prominent in recent years. However, there is currently no enforceable standard or building code for the design and construction of ecoroofs across the United States (Kraupa, 2014). Further research is needed to determine how ecoroofs respond to roof motion and to develop an appropriate design standard.The...
Structurally efficient and cost-effective solutions are needed to extend the service-life of deficient and aging highway infrastructure around the world. One critical need is to increase the flexural strength of older reinforced concrete (RC) structures to carry heavier and more frequent loads. Titanium alloy bars (TiAB) offer a new opportunity...
The Cascadia Subduction Zone has recently been identified as a source for an impending great earthquake. The potential of a large earthquake has created widespread interest into the resiliency of lifelines within the potentially affected areas. One critical lifeline is the electrical distribution and transmission systems which relies on legacy...
Aging and deficient infrastructure has become a major problem throughout the world. This is particularly evident in the case of reinforced concrete (RC) bridges. The cost of replacing these bridges is often prohibitive, thus engineers must find ways to strengthen them. Many older RC bridges predate the modern understanding of...
Large numbers of reinforced concrete deck girder (RCDG) bridges were built during the highway infrastructure boom of the 1950's. The advent of standardized deformed steel reinforcing bars during this time allowed for straight bar terminations in flexural tension regions. Designers of the time terminated reinforcing bars where they were no...
Failure of a gusset plate that caused the I-35W Bridge collapse in Minneapolis, MN resulted in mandated rating of connections by the Federal Highway Administration (FHWA). Rating connections requires material properties as an input. The material properties are generally reported on the available detailed drawings for bridges. However, some bridges...
Open grid steel bridge decks have been in use for nearly a century. These open grid decks provide an economical and lightweight alternative to traditional reinforced concrete decks. As the transportation infrastructure continues to deteriorate, open grid decks can be used as a cost effective way to rehabilitate structurally deficient...
The research presented here is a study to determine the effect of shear reinforcement corrosion on the shear capacity in conventionally reinforced concrete (CRC) bridge elements. A total of 14 CRC beams were tested using three stirrup spacings (8, 10, and 12-inch). Six of the beams included the influence of...
An experimental study of a passive energy dissipation tension-compression yielding brace or buckling restrained brace has been conducted. The Confined Yielding Damper (CYD) consists of a steel yielding core confined within a tube filled with non-cohesive media. The external tube and confined non-cohesive media provide lateral stability to the core...
The Astoria-Megler Bridge is a 6.6 kilometer (4.1 mile) long bridge, connecting Oregon and Washington on US 101, with a continuous steel truss main span of 376 m (1232 ft). It is the second longest main span bridge of this type in the world. Due to vortex shedding, some of...
The collapse of the I-35W Bridge in Minneapolis, MN on August 1, 2007 brought into question the design and inspection of gusset plates in steel truss bridges. The experimental tests performed in this research study the sway-buckling strength and behavior of large-scale steel gusset plates in an isolated truss connection....
Performance evaluation of conventionally reinforced concrete (CRC) bridge superstructure elements with diagonal cracks is of interest to the bridge engineering community. Standardized methods to predict service-level stress magnitudes in cracked bridge girders under combined bending and shear forces are not available. An analysis procedure was developed to determine the response...
Increasing load magnitudes and loss of reinforcing steel cross-sectional area from corrosion creates the potential for low-cycle fatigue (LCF) in conventionally reinforced concrete (CRC) bridge girders lightly reinforced for shear. LCF of reinforcing steel may be of particular concern. Little data are available for LCF of reinforcing steel without stress...
Fiber reinforced polymers (FRP) are becoming more widely used for repair and strengthening of conventionally reinforced concrete (CRC) bridge members. Once installed, the repair may be exposed to millions of load cycles during service life. The anticipated life of FRP repairs for shear strengthening of bridge members under repeated service...
The behavior of stirrups engaged by diagonal cracks and under service loads is
largely unknown. Full-size laboratory specimens were loaded to induce diagonal
cracks and subjected to high-cycle fatigue loading to represent a service life of 50
years. Tests indicated little change in the average stirrup stress range and mean...
The LRFR Manual, within commentary Article C6.4.4.2.3, contains provisions for development of site-specific live load factors. In Oregon, truck Weigh-in-Motion (WIM) data were used to develop live load factors for use on state-owned bridges. The factors were calibrated using the same statistical methods that were used in the original development...
Large numbers of vintage reinforced concrete deck-girder bridges remain in the national bridge inventory. Many of these exhibit diagonal cracking and other distress. Due to the design practices of the time, it is common to observe cracks at locations where flexural reinforcing steel is terminated along the span. The presence...
Large numbers of reinforced concrete deck girder bridges that were constructed during the
interstate system expansion of the 1950s have developed diagonal cracking in the stems.
Compared to the present AASHTO-LRFD standards, the provisions of the 1950s allowed
for higher shear stress in the concrete, thus reducing the amount of...
Many bridges along the Gulf Coast of the United States were damaged by recent hurricanes, and many more are susceptible to similar damage. This research examines performance of common anchorage connection details for AASHTO Type III prestressed concrete girders used by some transportation agencies. Full-scale specimens were fabricated and tested...
Ponding of water on roof systems leading to collapse causes expensive damage and jeopardizes the life safety of building occupants. Current building codes and design specifications for flat roof systems offer minimal guidance in designing for ponding loads. The present research investigated ponding load effects on a long span, lightweight...
A methodology was developed to permit rectification and metrification of digital images of steel truss gusset plate connections. The approach will enable rapid and accurate collection of field measurements as compared to traditional methods to enable structural evaluation of gusset plate connections. The program enables the operator to quickly create...
Long-term durability of surface-bonded carbon fiber-reinforced polymer (CFRP) for shear strengthening of reinforced concrete (RC) bridge members remains uncertain due to the limited field experience with these materials. This paper provides experimental results from the testing of full-scale RC bridge girder specimens after exposure to prolonged environmental exposure and combined...
Long-term durability of surface-bonded carbon fiber-reinforced polymer (CFRP) U-wraps for shear strengthening of reinforced concrete (RC) bridge members remains uncertain due to the limited field experience with these materials. This paper provides experimental results from the testing of full-scale RC bridge girder specimens after exposure to prolonged freeze-thaw cycling. CFRP...
Current ACI design provisions for shear in reinforced concrete (RC) beams strengthened
with externally bonded carbon fiber-reinforced polymer (CFRP) U-wraps may not adequately account for the effect of scale. This paper describes tests of 6 geometrically scaled beams to identify possible scale effects of such beams. Results indicated that effective...
Article 1: Behavior of Epoxy Injected Diagonally Cracked Full-Scale CRC Deck-Girders.
Many cast-in place reinforced concrete deck-girder bridges (RCDG) remain in the national inventory and exhibit diagonal cracking. Epoxy injection has been in use for several decades as a method for sealing diagonal cracks, but the effects on girder behavior...
Capacity of transverse 1950's vintage reinforced concrete deck girder bridge bent caps with large straight bar anchorages were investigated and evaluated. Eleven subassemblage column specimens were examined with different anchorage lengths, bar groupings, amount of transverse steel, and externally applied axial force. Test results showed an increase in anchorage capacity...