On most land development bridge projects, the design process is usually not very well coordinated and there is not a single point of responsibility for the bridge project. All bridge projects constructed in the public sector and all building projects have one engineering firm that takes on the responsibility as the Structural Engineer of Record (SER). The fact is that the International Building Code requires that a SER be identified as the responsible party, but land development bridge projects are allowed to fall through the cracks.

Before going any further, let’s clarify the definition of a bridge. The federal government’s definition of a bridge is any structure with a span length greater the 20 feet. Structures less than 20 feet are considered culverts. However, some states call any structure over 10 feet a bridge.

Most land development bridge projects do not have a SER representing the owner, yet it is in the best interest of the Civil Engineer of Record (CER) and the owner/developer to gain the advantages and value that a SER provides.

Project Management Common Practice
Much of our understanding of the common practices employed by civil engineers and land development project managers is based on experience working as a Specialty Structural Engineer (SSE) for pre-cast concrete manufacturers designing pre-cast bridge components. The practices include:

No SER on Team – It is rare that a Structural Engineer of Record (SER) is involved in the design or construction of a land development bridge. The major flaw in this approach is that no one is looking out for the best interests of the owner/developer with regards to the bridge, and as we all know, bridges are expensive and laden with liability.

Civil Engineer/Developer Rely on Vendor – If a SER is not on the team, the civil engineer or the land development project manager usually seeks out assistance from a bridge vendor for design advice. Most bridge vendors offer this assistance for “free,” but again as we all know “nothing is for free” and “you get what you pay for.” Obviously this cost is included in the price of the product.

Vendor Hires SSE – The bridge vendor hires a SSE to perform the structural design and details for the bridge. The SSE either works directly for or as a consultant to the vendor. The flaws in this approach include:

Limiting the bridge type alternatives to the products the vendor sells – if they only sell one product you may get a one size fits all solution.

The Specialty Structural Engineer (SSE) is working for the vendor and is looking out for the vendor’s best interest, which could be in conflict with the owner/developer’s priorities.

Since the vendor is paying the SSE for the structural engineering services, and this cost reduces the vendor’s profit, there is a natural tendency to reduce the comprehensiveness of the engineering services. Again, if a SER is not involved, the SSE needs to make assumptions regarding the design criteria that may not represent those of the owner/developer.

Minimal or No Geotechnical Information – All too often we have been involved in a land development bridge as an SSE, ready to perform the final design, and we find that there were no borings taken at the proposed location of the bridge. We then need to put the project on hold while this data is collected. This results in an otherwise unnecessary delay.

Drawings Not Coordinated – The design drawings prepared by civil engineering firms on land development projects are usually very well detailed and coordinated – except for the bridge aspects of the design. What we usually see is just a schematic plan and elevation with a callout for a certain prefabricated bridge system. The specified vendor is usually happy with this approach because they may have been working behind the scenes with the civil engineer and have developed their designs and details to adequately price the job. However, other vendors in the marketplace are at a huge disadvantage because they have to scramble in the 11th hour to put together their competing design (with minimal information) in order to provide a price quote.

No Fabrication Plant Inspections – The inspection of the bridge elements during fabrication in the plant by an independent person (like a SER) is rarely conducted on land development bridge projects. The cost of the prefabricated bridge systems is usually over six figures. Having an inspector who is representing the SER perform an inspection during fabrication (especially for pre-cast concrete) is cheap insurance to guarantee you are getting what you ordered

Design-Build Bridge Projects – We almost never see a SER involved in land development jobs that use design-build as the procurement method and this is where the owner/developer would benefit the most from having a professional on their side looking out for their best interest.

Project Management Best Practices
Hire a Qualified SER – The CER or land development project manager should hire a qualified SER to assist during the planning, design and construction phase of the bridge project. The earlier the better. The SER’s qualifications should include:
• Familiarity with the land development process
• Familiarity with the prefabricated bridge systems on the market
• Familiarity with the custom built bridge alternatives
• Past experience designing land development bridges
• Familiarity with the aesthetic treatments that are prevalent on land development bridges.

Get Deep Soil Borings Early – For all bridge structures (spans over 20 feet), we recommend getting at least one soil boring per substructure as early in the project as possible. The Standard Penetration Test (SPT) should be employed and the borings should be extended to bedrock or refusal.

Perform a Bridge Type Study – For most bridges, it is desirable to have the SER perform a bridge type study. During the study the SER:
• Reviews the feasible bridge type alternatives
• Coordinates with the CER and geo-technical engineer
• Coordinates with the various bridge system vendors
• Performs cost estimates

Determines the advantages and disadvantages of each alternative

Prepares a conceptual plan, elevation and typical bridge section

We also recommend that the land development project manager should finalize his decision on the preferred bridge system alternative, and the preferred method for procurement, during the bridge type study phase. The typical procurement methods to consider include design/bid/build, fast track or design/build.

Develop Preliminary Bridge Plans – Regardless of the determined procurement method, we recommend the SER prepare preliminary bridge plans (30% plans) for the selected or preferred alternative. During this phase the SER performs further design and coordination with the CER, geotechnical engineer and the vendor’s SSE. These plans should be submitted to all the project stakeholders for review and comment before proceeding – i.e. developer, CER, geo-tech, municipalities, utility owners, state DOT, environmental agencies, etc. The SER also refines the bridge project cost estimate.

Fast Track Approach – If a fast track approach is followed for procurement, we recommend using the preliminary bridge plans (30%) to solicit price quotes. A detailed list of final design criteria and material specifications should be included on the plans. If a prefabricated bridge system is involved, a clear delineation of responsibilities between the SER and the SSE should be provided.

Design/Bid/Build Approach – Using the traditional design/bid/build approach, the SER develops the final design drawing and specifications for use by the developer in soliciting bids. We also recommend:
• Reference state DOT specifications - not specifications provided by a bridge system vendor
• Include as many “or equal” bridge systems as feasible
• Include a sample construction contract in the bid documents
• Require an itemized bid or schedule of values
• Request a schedule and completion date

Require a Certification at Completion – At the completion of the bridge construction, the SER should provide a letter, to the owner/developer, “certifying” that the bridge was constructed in accordance with the design and drawings. To enable the SER to provide a letter of certification, the SER needs to provide services during construction that include:
• Reviewing vendor’s shop drawings 
• Performing inspections during fabrication at the vendor’s plant
• Performing on-site field inspections at critical stages
• Preparing a set of “Record Plans”

Inspection of Privately Owned Bridges – For the safety of the traveling public, all land development bridges should be inspected by a professional engineer on a regular interval. All publicly owned bridges are inspected once every two years. The bridge inspection report should document all bridge deficiencies and recommend maintenance repairs. The developer should also consider including the cost of the biennial inspections and an estimate for bridge maintenance in the budget for the community association.

Conclusion
Land Development Project Managers and their Civil Engineer of Record should select a qualified Structural Engineer of Record to work with them on land development bridge projects (as early in the project as possible) for reasons that include:

Adds value to the project team by adding an expert in the field that has the teams objectives as a top priority

The SER provides non-biased recommendations as to the most appropriate and cost effective bridge system solution that is site specific
Increases the probability that the bridge project runs smoothly without unanticipated delays

Reduces the overall cost of the project and increases the quality of the final product

Provides the necessary checks and balances that are desirable in the coordination and administration of the contracts with the bridge vendor and their specialty structural engineer, the geo-technical engineer and the contractor SLDT