Vibration Isolation of Residential Building near Metro and Freight Train Tracks

Location: 121 E. Route 66, Glendora, CA

Products Used:

Developer: Avalon Bay Communities

Architects: Architects Orange

Acoustical Engineer: Eiler Associates, Inc.

Structural Engineer: Gouvis Engineering Consulting Group

Vibration Isolation of the Avalon Communities Glendora

Avalon Bay Communities, a member of the S&P 500, is building a 198-unit mixed-use development at a location adjacent to existing railway tracks in Glendora, CA, about 20 miles east of Los Angeles. The current primary noise sources in the vicinity of the project site are traffic noise from nearby roads, and railway noise from the adjacent freight railroad. However, the future noise environment would consist of the same sources, as well as the additional noise from the proposed Metro Gold Line Foothill Extension. Acoustical calculation shows that the future combined noise levels at proposed building façade would range from 63.4 CNEL (Community Noise Equivalent Level) to 69.9 CNEL, exceeding the minimum requirements of 45 CNEL max in residential spaces. Regupol vibration isolation is needed to bring the CNEL into compliance.

The overall noise environment at the project site is influenced by railway traffic traveling on a two rail, two-way train track system located immediately north of the project site. These tracks are used by the Burlington Northern Santa Fe (BNSF) railroad, which operates daily along the corridor. At the time of design no schedule of anticipated trips from the Metro Gold Line extension is available, so for a worst-case estimate, it was assumed that there would be approximately 300 trips per day on the nearby Metro Gold Line track. Each train was evaluated at a speed of 65 mph.

As railway vibration is expected to be exposed to vibration levels greater than FTA recommended thresholds, structural mitigation is required for any concrete slab in vicinity of the railroad to reduce ground-borne railway vibration to below a level of significance. Regupol® Vibration and Regufoam® Vibration Isolation products are used to isolate strip foundations and slabs on grade, and achieve natural frequencies of 9 – 12.5 Hz for enhanced acoustic performance within the living spaces of concern.

The collaboration with Eilar Associates and Architects Orange was incredible. Their level of professionalism and the openness for such isolation design makes us grateful for having had the opportunity of working with them.

Images courtesy of avaloncommunities.com