As many of you already know, replacing the bridge that carries Mulholland Drive over the 405 freeway is part of the I-405 Sepulveda Pass Improvements Project. The main aim of the project is to build a carpool lane on the northbound side of the freeway between the 10 and 101 freeways.
Because the freeway is being widened to accommodate the new lane, the Mulholland Drive bridge must be replaced. The question is whether a new bridge can be built next to the existing one to keep local traffic moving. Here’s an update from Metro CEO Art Leahy’s daily email to staff:
The I-405 Sepulveda Pass Improvements Project Director presented plans for the Mulholland Bridge realignment over the I-405 freeway to the Mulholland Design Review Board last night. With over 100 people in attendance, staff presented numerous alternatives that had been reviewed and requested in order to establish a favorable recommendation that could be forwarded to the Los Angeles City Planning Commission in support of the Mulholland Bridge realignment.
A realignment of the bridge would allow the project to build a parallel bridge while the existing bridge remains in place and fully accessible and open to traffic during construction, it would necessitate only one weekend of full freeway closures during demolition rather than two, there would be no need to relocate utilities and it would improve the intersection from a Level of Service F to a Level of Service C for current users.
The Design Review Board passed a motion requesting the following:
• Metro returns with an alternative that maintains the recommended alignment presented, but shows a continued flow on Mulholland Drive over the I-405, rather than a “t-intersection.”
• Submit a complete application to the Design Review Board with responses to letters submitted by the Santa Monica Mountains Conservancy, The Brentwood Residents Coalition and the Bel Air Sky Crest Home Owner’s Association that include queries about plans for wild life, landscaping, vistas and the aesthetics of the bridge.
• Engage the services of a “world class architect” to design an “extraordinary” (re)design of Mulholland Bridge that supports the Mulholland Scenic Specific Plan mission.
Metro staff is considering the impact to process of bridge type selection already vetted and completed and will make a decision on path forward in the next week.
Staff from the offices of Supervisor and Metro Director Yaroslavsky, Councilmembers Koretz and Rosendahl and Assembly members Feuer and Pavley attended the hearing, as well as staff from the City of Los Angeles Department of Transportation and Planning Commission.
David – the embankments (earthen slopes) between the abutment foundations (where the ends of the current bridge rests) and the the column foundations are actually part of the structural support system for the abutment foundations (see http://thesource.metro.net/wp-content/uploads/2011/01/East-View-of-Mulholland-Bridge-Under-Construction-rev2.jpg for a good view). You can not remove this soil without affecting the structural support (side load) of the abutement foundation.
I’m sure if this had been a viable option, it would have been in the original scope of the project written by CalTran’s Design Engineers.
Do you have any images of the proposed bridge design?
Let me ask around and see what I can find.
Editor, The Source
That was quick answer — I’m told there are no renderings available while the design and location of the bridge are still being designed.
Editor, The Source
The best solution would be to route the new northbound on-ramp lanes from Skirball to the right (East) of the current bridge footings and call it a day! By shifting the on-ramp in such a way, you would have room to add the carpool lane in the current footprint of the existing lanes. This is the most financially prudent course that would cause no disruption to the Mulholland bridge traffic.