D’Appolonia’s experience related to transportation and infrastructure includes projects for highways, bridges, tunnels, soil and rock embankments and slopes, retaining walls, culverts, streambank stabilization, pavements and other related infrastructure features. Our staff has extensive experience with respect to application of geotechnical and structural engineering expertise to infrastructure projects. Our familiarity with current engineering technologies and agency requirements allows us to develop safe, cost-effective and constructible designs for new facilities, and to repair, rehabilitate or modify existing facilities. We apply both traditional and innovative technologies to solve engineering problems.

Our experience with respect to transportation and infrastructure includes:

• DESIGN OF HIGHWAY CUTS, FILLS, SLOPES
  AND RETAINING STRUCTURES
• DESIGN OF BRIDGE FOUNDATIONS
• DESIGN OF TUNNELS AND OTHER BURIED
  STRUCTURES
• VALUE ENGINEERING STUDIES

Geotechnical engineering is the mainstay of D’Appolonia’s professional practice. The design of cuts and fills associated with highway construction are fundamental elements of that practice. We are experienced in planning and implementing subsurface exploration programs in soil and rock and in soil and rock sample testing and interpretation of test data. We routinely develop plans and specifications for excavation and backfill and we have experienced staff that monitor construction work, including fill compaction. We are experts in the design of soil slopes and slope retaining structures. We frequently implement innovative slope retention designs employing geosynthetics and specialty construction techniques. We have received awards and other recognition for projects that have employed innovative designs.



Design of Bridge Foundations

D’Appolonia is experienced in the design of foundation support for bridge structures such as abutments and pier foundations. Our services have often been utilized in situations with difficult subsurface conditions where conventional designs could not be implemented. These conditions have included loose or highly compressible surface soils and highly variable conditions such as karst terrain (i.e., solutioned limestone with large voids infilled with soft material). Our experience includes designing bridge abutments on foundations ranging from spread footings to deep piles and supporting bridge piers on minipiles. For a major limited-access highway in Western Pennsylvania crossing a large area of saturated fine coal refuse, we implemented a design involving mixing of grout with the fine coal refuse to stabilize the subgrade. We are also experienced in the application of specialty geotechnical construction techniques to bridge and highway construction.



Design of Tunnels and Other Buried Structures

D’Appolonia has extensive experience in the design and construction of tunnels for sewer systems, mass transit lines, stormwater collection systems, and hydraulic feeds associated with hydroelectric power generation and cooling water supply for electric utilities. The subsurface conditions for these projects have varied from hard rock to weak soils, and construction techniques have ranged from lateral underground boring to cut and cover. For these projects, we typically perform detailed subsurface exploration programs that include geologic mapping, soil and rock sampling and extensive laboratory testing of these samples, and geophysical borehole logging and seismic cross-hole testing. Our scope of work has included design of the tunnel liners and openings including design of rock bolt/dowel spacing, location of rock reinforcement and implementation of grouting programs. We have also evaluated construction effects on adjacent structures and utility systems, and implemented ground monitoring instrumentation programs.



Value Engineering Studies

Value engineering is a systematic process for reducing the total cost of a product or service. Value engineering involves more than looking for alternate ways to achieve the same result; it also entails identifying the required functions of the components of the product or service and determining the least cost means to provide those functions while retaining acceptable factors of safety. Value engineering therefore requires expertise in (1) design review, (2) alternative engineering design, (3) constructability evaluation and (4) cost evaluation. D'Appolonia provides value engineering services to owners, designers and contractors for projects related to foundations, bridge abutments, retaining wall structures, underground structures, and ground water control systems. Typically, the outcome of these studies is a substantial reduction in construction cost for our clients.