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US 71 Market Street

US 71-LA 1 bridge over ICG railroad was built in 1940 in downtown Shreveport, LA. Consisting of a two-bridge structure, each having 15 steel beam spans, 7 reinforced concrete spans, and reinforced concrete approach spans. The bridge covers a length of 850’ and a width of 20’. The US 71-LA 1 bridge carries or crosses multiple modes of transportation, while providing two 5’-11 ½” sidewalks and crossing two railroad tracks.

LA DOTD had posted the bridge for a speed limit of 25 MPH and posted load limits of 20T-35T. Based on further concerns LA DOTD assigned SDR with the task of performing a feasibility study on the twin two-lane bridge. SDR performed a thorough document review, hands-on inspection, and surveying to assess the conditions of the bridge. SDR field inspections indicated that the physical condition of the structure ranged from “fair” to “critical,” depending on their location.

Based on the structure’s old age, displacement, and severe exiting conditions, SDR proposed replacement of both structures and provided two alternate designs. One alternative utilized precast-prestressed concrete to satisfy the railroad’s minimum vertical and horizontal clearance. A second proposed alternative utilized a combination of precast-prestressed concrete girders and heavy, shallow rolled beams to meet railroad clearances. In both cases, span lengths from 80’ to 90’ were recommended to achieve maximum efficiency and to avoid interference with existing bridge foundations.

US-90 MACARTHUR DRIVE INTERCHANGE PHASE Phase II

US-90 MACARTHUR DRIVE INTERCHANGE PHASE II

Constructed in the late 1950s, the Westbank Expressway is a six-lane urban, divided and elevated freeway. The elevated section extends from Westwood Drive in Marrero, Louisiana, to the Crescent City Connection Bridge across the Mississippi River, connecting the Westbank communities of Jefferson Parish with downtown New Orleans, Louisiana. Each structure of the elevated expressway includes three 12’ travel lanes, a 6’ interior shoulder, and a 10’ exterior shoulder. The bridges consist of trapezoidal concrete girders supporting a 7½”-thick concrete slab. The superstructure is supported on concrete single pier columns with pile-supported footings. The elevated freeway is supplemented by a six-lane divided service road system at ground level, running parallel to and outside of the twin elevated bridge structures, with ramp connections to major arterial cross streets at intervals of 0.7 to 0.9 miles throughout its length of nearly six miles.

SDR was tasked with providing access ramps from the service roads to the elevated freeway to and from the east and to reduce the distance between successive westbound off-ramps and eastbound on-ramps. SDR designed 22-spans of off-ramp and 24-spans of on-ramp. The design consisted of complex structural elements: precast-prestressed LU-girders and LG-girders, inverted T-cap beams, complex columns, and foundations. SDR also provided precise construction sequence, instructing the removal of existing structures to accommodate the new structure.

CR 514 Bridge Over I-75

Repair of CR 514 Bridge over I-75 in Sumterville, Florida was completed by SDR. The bridge was struck by an over-height truck, causing severe damage to the exterior prestressed concrete girders, including rupture of several prestressing strands.

Before SDR’s involvement, it was determined to replace the girder. SDR was tasked to assess the damage and its impact on the structural integrity of the girders using its in-house developed damage assessment tools, design of the repair, and develop repair details. Repair of the girders included splicing of ruptured prestressing strands, correcting alignment and rotation of the bottom flange, restoring the concrete section, substituting ruptured stirrups using Near-Surface-Mounted technique, and applying externally bonded CFRP to confine the restored section and to provide redundancy to the shear strength. These repair methods allowed I-75 to remain open during construction.

SHERIDAN STREET BRIDGE OVER FLORIDA TURNPIKE

The Sheridan Street bridge spans 195 feet in four spans over the Florida Turnpike. The superstructure of the bridge comprises 12 precast prestressed concrete AASHTO Type II beams with a roadway width of 60 feet.
The southbound lane was impacted by an over-height vehicle, causing damage to the exterior beam and four interior beams. Damage was in the form of section concrete loss, exposure of prestressing strands, rupture of prestressing strands, and excessive cracking.
In-house developed software, Smart Bridge Suite, was used to analyze the superstructure, to determine the impact of damage on the structural strength of the beams and to design the rehabilitation work.
Repair work included splicing ruptured prestressing strands, restoring concrete section using polymer modified concrete, using externally bonded longitudinal CFRP sheets and transverse U-wraps. The use of advanced composite materials allowed the damaged beams to be repaired instead of replaced, while providing accelerated construction.

STRUCTURAL EVALUATION OF RC T-BEAM BRIDGES THROUGH LOAD TESTING & FEA

Structural evaluation through load testing, coupled with advanced Finite Element Analysis (FEA), is a powerful tool to load rate posted bridges with the aim of removing the current posting. Based on SDR’s vast experience in structural evaluation and load testing, bridges can carry much higher loads than those estimated by design code equations. Load testing captures actual behavior of the structure (load distribution) and accounts for strength enhancing factors not included in design.

The LA 182 bridge over Berwick Bay is controlled by reinforced concrete T-beam spans. SDR was tasked with performing structural evaluation though load testing of the T-beam spans with the aim of removing the current posting.Test results, along with the FEA, revealed that, due to the support conditions of the slab, partial fixed end moments were developed, causing significant reduction in mid-span moment compared to moment calculated assuming simple-beam action. Load rating of the bridge was carried out in light of the testing findings and FEA results, resulting in an increase of load rating factor from 0.85 to 1.23.

I-10 OVER US-19 IMPACT DAMAGE BRIDGE REHAB

The I-10 over US 19 bridge is located in the center of Jefferson County near Monticello, Florida. The bridge spans 243.33 ft. over US 19 and consists of four (4) spans. Two spans are 44.5 ft. long, comprising two Type III AASHTO beams for the exterior beams and three Type II AASHTO beams for the interior beams. Two spans are 77.16 ft. long, comprising seven Type III AASHTO beams.
Span 3 was impacted by an over-height truck causing severe damage in the fascia beam (beam 7) and the interior beam (beam 6). The vehicle impact resulted in significant section loss, cracking, and rupture of prestressing strands.
In-house developed software-Smart Bridge Suite was used to analyze the superstructure accounting for the damage to determine the impact of damage on the structural strength of the beams and to design the rehabilitation work.
Repair work included splicing rupture prestressing strands, restoring concrete section using polymer modified concrete, using externally bonded longitudinal CFRP sheets and transvers U-wraps. The use of advanced composite materials allowed the damaged beams to be repaired instead of replacement, while providing accelerated construction.

I-10 EAST AT HIGH RISE BRIDGE FIRE DAMAGE REPAIR

I-10 East at the High-Rise bridge was severely damaged due to fire. The damage is located on the eastbound side of I-10 at Bents Nos. 2-E/W and extends into spans 17-E/W and 18-E/W. The damaged members included columns, cap beams, girders, risers, bearing, and deck slab.
The scope included performing in-depth inspection of the fire damage and assessment of fire impact on the structural performance of the bridge, design of the rehabilitation system for the different elements of the superstructure/substructure, and providing full construction support.
Possible rehabilitation alternatives were investigated considering cost-benefit ratio, traffic impact, and past experience. Designed rehabilitation technique encompassed restoring the concrete section and the use of advanced composite materials (Fiber Reinforced Polymers) to regain the strength of the damaged structural members. Selected alternative allowed for construction while avoiding closing the bridge, where only partial lane closure was required for very limited number of days.

STRUCTURAL EVALUATION OF SLAB BRIDGES THROUGH LOAD TESTING & FEA

Structural evaluation through load testing, coupled with advanced Finite Element Analysis (FEA), is a powerful tool to load rate posted bridges with the aim of removing a current posting. Based on SDR’s vast experience in structural evaluation and load testing, bridges can carry much higher loads than those predicted by design codes due to load testing capturing actual behavior of the structure (load distribution) and accounting for strength-enhancing factors that were not included in design.
LA-1 bridge over Lockport Canal was built in 1959. The bridge load rating is controlled by the reinforced concrete slab spans. SDR was tasked to perform the structural evaluation though load testing of the slab spans with the aim of removing current posting.
Test results, along with FEA, reveal that due to support conditions of the slab, partial fixed end moments developed, causing significant reduction in mid-span moment as compared to moment calculated assuming simple-beam action. Furthermore, the slab behaves in a two-way bending action rather than the one-way bending action used in conventional design and load rating. Load rating of the bridge was carried out in consideration of the test findings and FEA results, which resulted in an increased load rating factor, from 0.75 to 1.22.

WILLIAMS ROAD/SW 66 BRIDGE OVER I-75

The Williams Road/SW 66 Street bridge over I-75 in Ocala, Florida was built in 1989. The bridge consists of four (4) spans with a total bridge length of 272.5 ft. The superstructure comprises four (4) AASHTO Type III precast prestressed concrete beams. The bridge was impacted by an over-height truck, causing damage to exterior and interior beams. Damage to both beams was in the form of partial loss of concrete section in the bottom flanges and webs with exposed prestressing strands, but with no rupture of prestressing strands. During inspection it was also found that the exterior beam had old repair at the right end of the beam and exhibited signs of distress, e.g. cracking and delamination.
Repair of the beams included restoring the concrete section of the bottom flanges and webs. Also, externally-bonded CFRP was applied to confine the restored section and provide redundancy to the shear strength. The repair method allowed I-75 to remain open during construction.

STRUCTURAL EVALUATION OF RC T-BEAM BRIDGES THROUGH LOAD TESTING & FEA

Structural evaluation through load testing coupled with advanced Finite Element Analysis (FEA) is a powerful tool to load rate posted bridges with the aim of removing current postings. Based on SDR’s vast experience in structural evaluation and load testing, bridges can carry much higher loads than those estimated by design codes equations. Load testing captures actual behavior of the structure (load distribution) and accounts for strength enhancing factors not included in design

The load rating of LA 182 bridge over Berwick Bay is controlled by reinforced concrete T-beam spans. SDR was tasked with performing the structural evaluation though load testing of the T-beam spans with the aim of removing the current posting.
Test results and FEA reveal that, due to support conditions of the slab, partial fixed end moments are developed, causing significant reduction in mid-span moment compared to moment calculated assuming simple-beam action. Load rating of the bridge was carried out in consideration of the test findings and FEA results, resulting in an increase of load rating factor from 0.85 to 1.23.