We are committed to help solve the deteriorating bridge problem by using our innovative Ultra-High Performance Concrete rehabilitation methods.
Learn about our successfully completed bridge projects addressing the bridge owner’s needs for long-term preservation solutions.
The Ellison Avenue Design-Build project involved the replacement of a 115-year-old multi-span bridge over the LIRR Main Line in Westbury, NY. The project scope included the design and reconstruction of the bridge from the abutment footings up, including installing a new single-span precast prestressed concrete superstructure with integral wearing surface. Shear Keys for the precast superstructure were filled with 30 CY of 20 KSI UHPC followed by diamond grinding to achieve the final roadway profile. The project was situated in a residential neighborhood, limiting site access and linearizing construction progress.
Construction on the project was challenging because of limited space at the worksite and work over an active commuter rail line main corridor. Design complexities included engineering a new roadway profile that neared maximum permissible grading limits heavy profile in the roadway and engineering a new approach sidewalk and parapet that did not impart additional loads on existing substructures of unknown capacity.
Site logistics and access issues were solved by installing temporary access ramps from the roadway down to the LIRR Right-of-Way below, allowing ease of access to track level for equipment and workers. This also facilitated work during the two weekend outages allotted on the project, for which planning began at the onset of the project to ensure continuity of LIRR operations. Construction means and methods were optimized to minimize work that required track outages, resulting in returning tracks back to service ahead of schedule.
Roadway grading design issues were solved by selecting a shallow precast prestressed concrete beam superstructure, reducing the height of the bridge. The use of a precast superstructure also minimized impacts to LIRR rail traffic below. Helical piles were utilized to transfer loads from a new approach sidewalk & parapet through existing crib-type retaining walls along the bridge approaches, eliminating the need for a costly and intrusive replacement of the crib walls
In total, 30 cubic yards of UHPC were produced and installed during a single casting day. The precast bridge units were prepared for the UHPC material by casting with an exposed aggregate finish which provides an excellent bond with UHPC. Utilization of PBE with UHPC shear keys allowed the shutdown of rail traffic below the bridge to be shortened to two weekend closures. This reduced the impact of the bridge work to a LIRR trains and the traveling public. The use of UHPC joints and PBE also allowed a reduction in the height of the bridge which corrected an existing bridge profile issue.
The bridges were originally constructed for a new grade separated interchange on State Route 1 (SR-1) at Bower Beach Road. Two 120 ft long and 42 ft wide bridges were constructed with a cast-in-place concrete deck on steel girders.
After the initially completed concrete bridge decks were surveyed, it was determined that the cambers of the steel beams were not even. This resulted in having the top rebar mat in the center of the bridge deck with insufficient concrete cover and protection. DelDOT was in search of a solution that would provide enough protection of the top rebar mat, while keeping the designed cross slopes and horizontal curve of the bridges.
A UHPC overlay was selected as the preferred alternative repair method due to its great durability resistance and water tightness. The UHPC overlay functioned as grade repair, waterproofing element and road surface. In addition, it can function as a structural element under compression but this was not considered in the design of the repair method. The UHPC overlay thickness varied between 1¾” to up to 5” in local areas with an overall average thickness of approximately 3”.
The surface of the existing concrete was prepared using hydrodemolition at a depth of ¼” in order to ensure sufficient bond of the UHPC overlay to the concrete substrate.
Given the low temperatures in February 2019, heating was required to prevent the thin UHPC overlay from freezing and allowing the UHPC overlay to bond properly to the existing concrete deck. This heating was accomplished with forced air and hydronic systems placed below and above the bridge deck.
In addition, heating of the UHPC premix and mixing water was required to maintain proper UHPC workability during placement.
The selected material was a Lafarge Holcim Ductal overlay formulation with 3.25% steel fibers. In order to achieve proper strength development, the freshly placed UHPC overlay was tented and heated immediately after installation.
Twenty-four hours later, the tent was removed and hydronic heating hoses were placed for three days of curing. Using this curing procedure, the UHPC overlay reached strengths between 11,000 psi and 13,000 psi almost achieving the design strength of 14,000 psi within this short time period.
Staging of the overlay construction included 3 paving lanes (18 ft, 12 ft, 12 ft) and construction joints were located between the road lanes. The final road surface preparation included diamond grinding of the UHPC surface in order to meet the road surface requirements for smoothness and microtexture.
In 2017, Cramer & Associates Inc. of Grimes, IA was awarded the main contract to rehabilitate the deck of Floyd River Bridge as part of a large bridge rehabilitation package. WALO Iowa LLC was chosen as a sub-contractor for the UHPC overlay project, due to our expert know-how and experience with the material. WALO has successfully completed a variety of UHPC applications in Europe, most significantly the 2.3-mile-long Chillon Viaducts, alongside Lake Geneva in Switzerland. Recognized by the American Concrete Institute (ACI), the Chillon Viaduct rehabilitation was the first ever project to use a machine to install a UHPC layer on bridge decks.
The 9,020 sq. ft UHPC overlay job was completed in less than ten workdays, by our Swiss-American construction team and with support from Cramer & Associates Inc. and LafargeHolcim North America.
One lane of the bridge remained open for public at all times for the course of the project to minimize traffic disruption to the traveling public.
The Chillon viaduct is located in Switzerland, over the east end of Lake Geneva, south-east of Montreux. It comprises two parallel 1.4 mile long prestressed concrete box girder bridges, bearing the east and westbound lanes of the Swiss A9 highway.
Built in the 1960s, it was one of the most significant works in prestressed concrete for many years, so it was of great historical value to the area. Originally designed to sustain an estimated volume of 10,000 vehicles per day, it is currently being used by 60,000 vehicles daily.
The bridge was scheduled for deck rehabilitation, but an inspection of the viaducts revealed that they were significantly damaged and deemed structurally deficient. In various places, the concrete’s reinforcing bars had been corroded and the concrete itself was betraying signs of Alkali-Silica Reaction (ASR). On closer inspection, following hydrodemolition tests, Alkali-Aggregate Reactions (AAR) were also detected, which meant the mechanical properties of the concrete were compromised. If repairs were not undertaken, it is likely the structure would have needed complete rebuilding.
With an ever-increasing number of vehicles using the bridge, a solution was required to increase the shear, bending and fatigue resistance of the deck slab. The structure also needed any damage caused by ASR and AAR to be reversed, as well as waterproofing to prevent future damage and a significant improvement of its structural properties.
A thin steel rebar-reinforced Ultra-High Performance Fiber Reinforced Cement-based Composite (UHPFRC or UHPC) overlay was selected as the best and most cost-effective solution to meet the complex needs of the structure. The material has extraordinary strengthening and waterproofing qualities and, with the right skills and machinery, it is possible to place it extremely quickly, meaning that the carriageway could be closed for the least amount of time possible, minimizing disruption and costs.