FEATURED PROJECTS

PB&A served as Engineer of Record (EOR) for the temporary Support of Excavation for four underground stations comprising the Purple Line Extension. This high-speed rail alternative connects commuters traveling between downtown Los Angeles, the Miracle Mile, Beverly Hills, and Westwood. The design was complicated by the requirement to keep Wilshire Blvd. open as a live thoroughfare over the excavations. PB&A designed concrete decking panels to maintain vehicular and pedestrian traffic while excavation took place beneath.

For nearly fifty years, Pirooz Barar & Associates has been providing industry-leading structural engineering solutions for a wide variety of construction challenges. This image shows our expertise in deep excavations and internal bracing used in the La Brea station of the Los Angeles Metro Extension project.

L.A. METRO - HOPE STATION

PB&A served as Engineer of Record (EOR) for the temporary Support of Excavation for four underground stations comprising the Purple Line Extension. This high-speed rail alternative connects commuters traveling between downtown Los Angeles, the Miracle Mile, Beverly Hills, and Westwood. The design was complicated by the requirement to keep Wilshire Blvd. open as a live thoroughfare over the excavations. PB&A designed concrete decking panels to maintain vehicular and pedestrian traffic while excavation took place beneath.

JAMUL HOTEL AND CASINO

In 2012, PB&A, Inc. was retained by Marnell Companies to develop an innovative permanent shoring system for a 100‑ft‑deep excavation for an underground parking structure beneath a new casino. The constrained site bordered an environmentally sensitive area under California Department of Fish and Game jurisdiction, presenting significant geotechnical and site‑access challenges.

In 2022, PB&A was retained by Jamul Indian Village Development Corp. to design temporary and permanent excavation support for a planned 15‑story hotel addition and a new 5‑story parking structure requiring a 40‑ft perimeter retaining wall. Due to a pronounced east–west grade differential, a permanent soil‑retention system was required. PB&A developed a hybrid shoring solution to address site constraints and stakeholder restrictions, including:

Replacing soil nails with cantilevered cast‑in‑drilled‑hole (CIDH) piles where neighboring property lines prohibited nail encroachment.

Shifting and redesigning the wall adjacent to a sacred burn site (moved 5 ft) using cantilever CIDH piles.

Implementing a hybrid soil‑nail/CIDH system beside the cemetery to avoid intrusions into cemetery grounds.

The hybrid approach mitigated constructability, regulatory, and cultural‑resource constraints while providing robust, permanent earth retention for the project.

CARROL CANYON HOV LANE

PB&A was retained by AECOM to develop a value-engineered design for a permanent retaining wall to support the cut into the hillside at the I-5/805 junction, which accommodates the HOV lanes in both directions at the interchange.
A nearby wall to the north, designed by TYLIN, had a final construction cost of $27 million. PB&A, Inc. delivered a preliminary design for AECOM with a projected cost of $7 million and was credited with helping AECOM secure the contract. The wall was completed on time and under budget.

The permanent soil-nail design was the first of its kind approved by Caltrans for construction adjacent to active freeway lanes and was honored in 2017 with the California Transportation Foundation (CTP) and American Public Works Association (APWA) Project of the Year Award.

HONOLULU LIGHT RAIL

In 2017 PB&A was retained by STG (Shimmick, Traylor, Granite) to design three trestles for the HART (Honolulu Rail Transit) Project. The trestles span the Moana Lua Inlet, Kalihi Stream, and Halawa Stream and support construction of three stations serving the new aerial light-rail system in Honolulu — critical elements of the $8 billion, 20-mile elevated Oʻahu light-rail program (see attached ENR article, published July 15).

One particularly challenging task was the installation of a 332-foot-deep, 10-foot-diameter cast-in-drilled-hole pile at Kahili Inlet — possibly the deepest of its kind in the industry. The installation was complicated by the pile’s location in a riverbed underlain by roughly 100 feet of very soft clay. To support pile driving operations, temporary trestles were built at both sites; each trestle had to resist oscillator loads up to 1,000,000 lb as well as equipment loads of about 400,000 lb.

Predicting deformation of the 36-inch-diameter, 150-foot driven caissons that supported these trestles — while accounting for a 600-kip lateral load and 14,000 kip-ft of torque — proved sufficiently complex that we developed a dedicated white paper describing our solution. That paper was presented at the DFI SuperPile conference in Chicago.

TRANSBAY TRANSIT PROJECT

This 4 billion dollar project in Downtown San Francisco, called the “Grand Central Station of the West”, will replace the old Transbay Bus Terminal extending Caltrain and the California High Speed Rail to the underground station at the new transportation center. PB&A, Inc. was retained by Balfour Beatty Infrastructure to design the Internal Bracing System, Bridges and Trestle that made up the

Shoring/Excavation contract for this enormous undertaking in downtown San Francisco. The Internal Bracing System is designed to support the 60’ excavation, 3 City blocks long (1600 linear feet

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301 MISSION STREET

The design for the shoring of this 55’ deep excavation in a high profile, downtown San Francisco area, uses a system of Cross-Lot Bracing where the soils are predominantly bay mud, and having a water table 3 ft. below grade.The building will cover a large part of the city block, with 5 levels of parking below grade.

THE HEIGHTS

PB&A, Inc. was retained by Fairfield Residential Company, LLC to provide a value engineering design for an earth retention system supporting the development of a large-scale apartment complex adjacent to Friars Road in San Diego, California.

Challenge The previously designed earth retention system carried a cost of over $7,000,000. The sheer size of the hillside presented a significant engineering challenge, requiring a retaining wall exceeding 1,000 feet in length around the west, north, and east boundaries of the project, reaching heights of at least 100 feet at its tallest point.

Solution PB&A's value-engineered design approach focused on maximizing the efficiency of each soil nail—a critical factor that becomes increasingly important as wall height increases, particularly for structures exceeding 100 feet. This optimization was achieved through advanced technological analysis and a nuanced understanding of how output data informs the balance of critical design factors to arrive at the ideal engineering solution.

Results The PB&A value-engineered design delivered a 25% cost savings to the project, reducing the earth retention system cost by approximately $1.75 million while maintaining structural integrity and safety standards.

"Fairfield Fashion Valley is proud and pleased with the recently completed Soil Nail Wall System designed by PB&A. Tremendous effort and collaboration by PB&A with all the project stakeholders resulted in its success and striking appearance." — Eric Schwing, Project Manager, Construction, Fairfield Residential