The Martin’s Ferry Bridge carries local traffic on Bald Hills Road over the Klamath River near the intersection of SR 169. The six-span structure consists of three steel girder approach spans and three steel truss spans. The original structure was constructed in 1959. During the 1964 flood, the west end of the bridge from the abutment to the superstructure pin adjacent to pier 2 was destroyed. The destroyed portion the bridge was replaced the following year. In addition, the hillside at the northeast approach to the bridge is an active slide which has resulted in damage to abutment 7 and piers 5 and 6.
MGE was retained by the County to evaluate the condition of the bridge, complete a preliminary structural and seismic assessment, and prepare a retrofit/rehabilitation feasibility study to address the damaged abutment 7 and piers 5 and 6. A feasibility study was completed by MGE that addressed the cause of the damage, determined the feasibility of retrofit/rehabilitation, identified a recommended retrofit/rehabilitation strategy, provided estimates of construction costs, and provided a detailed work plan for completion of the engineering needed to execute the recommended retrofit/rehabilitation strategy. MGE during this time also assisted the County in the design of girder continuity plates to be installed at pier 6 as an interim measure to prevent catastrophic collapse of the structure. Upon acceptance of the findings of the feasibility study by Caltrans, MGE was contracted to complete an initial phase of work which included development of the Type Selection Study. The Type Selection Study which evaluated both replacement and rehabilitation was completed and presented to Caltrans at a Type Selection Meeting. Following the meeting, it was determined to retrofit/rehabilitate the existing structure. MGE under contract to the County completed the PS&E for the retrofit/rehabilitation of the structure.
On December 3, 2007, Caltrans closed this bridge and notified the Federal Highway Administration (FHWA) that the bridge was at high risk of collapse due to continued movement of the slide, and that an Emergency Repair was required. The County amended MGE’s existing contract to add the preparation of the PS&E for the emergency work. MGE completed the PS&E for the work within a 3 week period. This was done to expedite the completion of the work to allow re-opening the bridge to limited traffic. The design involved the development of plans for temporary supports that provided the necessary strengthening and would not impede the construction of the ultimate retrofit/ rehabilitation.
The temporary repair scenario included construction of temporary pier towers on either side of Pier 5, which had displaced over 19″, installation of CIDH buttress piles behind Abutment 7 to stabilize earth movement that caused the failure of the Abutment, and the addition of large diameter drainage galleries to provide positive drainage of the soil behind and below the eastern portions of the bridge. A monitoring system was installed to monitor ground water levels in the drainage galleries, movement of earth above and behind the bridge, and a system of monuments to track horizontal and vertical movements.
Client: County of Humboldt Department of Public Works
- Construction of the rehabilitation project was completed in early 2013
Project Manager/Bridge Project Engineer: Bob Sennett
Civil Project Engineer: Jeff Crovitz