We have an established reputation as one of the leading covered bridge rehabilitation engineering firms in PA. We have the specialized engineering skills to design the restorations of these unique and complicated structures. We understand the historic preservation of these structures plays a significant role in tourism.

The complexity of covered bridge projects ranges from simple in-kind replacement of deteriorated timber truss members so as to extend the structure’s useful life, to extensive rehabilitation projects where over 90% of the structural timber members have to be replaced due to deterioration. In some instances, the existing timber covered bridges were completely dismantled, deteriorated truss members replaced-in-kind, salvageable timber truss members re-used, and the bridge re-erected. No matter what the complexity the covered bridge, LDG has the experience to deliver.

Covered bridge projects

Several projects require modifications to the structural system by adding multiple steel I-beams to enable the covered bridge to carry legal loads. Other covered bridge projects require modifications to the existing timber truss systems to provide a load rating for the rehabilitated bridge that would be evident of the bridge’s load carrying capacity in its original as-built condition. Whether the project need is for the covered bridge to be designed for 3 Tons, its Original Load Carrying Capacity, or Designed to Carry Emergency Service Vehicles and/or Legal Loads; LDG has experience can design to suit the project need. Our experience includes developing a three-dimensional structural analysis to model the behavior of these unique structures. This allows us to better define the stresses in the structure, which will result in a more economical design, and ultimately save money.

Each of the covered bridge rehabilitation projects LDG has completed has resulted in a “No Adverse Effect” finding from the Pennsylvania Historical and Museum Commission (PHMC). PHMC has concurred with all our proposed rehabilitations. This type of record is a product of our team work approach and collaborative effort during the environmental review process and Section 106 Consultation Process. LDG has gone through these processes numerous times. We apply our experiences forward on each project with success.


  • 3-Dimensional Finite Element Analysis
  • Asset Management & Capital Improvement Planning
  • Bridge Design – Vehicular, Pedestrian, Railroad
  • Bridge Rehabilitation
  • Bridge Loading Rating Analysis
  • Bridge/Sign Safety Inspections
  • Construction Services
  • DEP Permitting
  • NPDES Permitting
  • Erosion & Sedimentation Control Plans
  • Feasibility Studies
  • Geotechnical Investigation
  • Grant/Funding Assistance
  • Highway Design
  • Hydrologic & Hydraulic Studies
  • Preservation & Maintenance Programs
  • Pavement Design
  • Public Involvement
  • Public Utility Commission Coordination
  • Rails-to-Trails
  • Right-of-Way Plans
  • Sign & Pavement Marking Design
  • Traffic Control Plans
  • Utility Coordination