Structural Peer Review Statement
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DEPT OF BLDGS321197058 Job Number ES589992790 Scan Code STRUCTURAL PEER REVIEW STATEMENT This structural peer review and report, dated 11 December 2017, is complete for the foundation and superstructure submission. Structural Peer Reviewer Name: William J. Faschan Leslie E. Robertson Associates Structural Peer Reviewer Address: 40 Wall Street, FL 23 New York, NY 10005 Project Address: 11 Hoyt Street, Brooklyn, NY, Block# 157, Lot# 1 Department Application Number for Structural Work: 321197058 Structural Peer Reviewer Statement: I, William J. Faschan, am a qualified and independent NYS licensed and registered engineer in accordance with BC Section 1617.4 and I have reviewed the structural plans, specifications and supplemental reports for 11 Hoyt Street, Brooklyn, NY, Block# 157, Lot# 1, Application # 321197058 and found that the structural design shown on the plans and specifications generally conforms to the foundation and structural requirements of Title 28 of the Administrative Code and the 2008 NYC Construction Codes. The Structural Peer Review Report is attached. New York State Registered Design Professional (for Structural Peer Review only) Name William J. Faschan Signature __________________ Date: 11 December 2017 /Seal Cc: Project Owner: Mr. Chris McCartin, 11 Hoyt Property Owner, LP Project Registered Design Professional: Mr. Bart Sullivan, McNamara Salvia 11 Hoyt Street, Brooklyn, NY Structural Peer Review Report P1120 Leslie E. Robertson Associates, R.L.L.P. Consulting Structural Engineers 40 Wall Street, 23rd Floor New York, NY 10005 Tel: (212) 750-9000 Fax: (212) 750-9002 http://www.lera.com [email protected] 11 December 2017 P1120 – 11 Hoyt Street 11 December 2017 Structural Peer Review Report Page 1 1. Introduction At the request of Tishman Speyer Properties, Leslie E. Robertson Associates, R.L.L.P. has conducted a Structural Peer Review of the foundation and superstructure design of 11 Hoyt Street, as required by the New York City Building Code section 1617. This report presents our findings and conclusions. The building is located at 11 Hoyt Street in Brooklyn, NY and the structural design was prepared by McNamara Salvia Structural engineers. 1.1 Documents Reviewed We have reviewed the following: Structural and Architectural Drawings, listed in Appendix A. Structural Design Criteria by McNamara Salvia, dated 1 Mar 2017, attached to this report as Appendix B. The geotechnical report, Geotechnical Engineering Study for 11 Hoyt Street, Brooklyn, Kings County, New York, dated 23 December 2016, by Langan, attached to this report as Appendix C. Preliminary Results – Wind-Induced Structural Responses, 11 Hoyt – Brooklyn, NY dated 30 August 2017 and supporting material, by RWDI, attached to this report as Appendix D. 2. Design Criteria We reviewed drawing S-001.01 General Notes, as well as the structural design criteria and geotechnical report. Our observations are discussed below. 2.1 Geotechnical Report In reviewing drawing S-001.01 and the geotechnical report from Langan, we found that recommendations made in the report were incorporated in the drawings and design criteria. 2.2 Structural Design Criteria For the Foundation Peer Review, we reviewed loading schedule information provided in drawing S-001.01. We find that the drawing includes a loading schedule appropriate for the types of occupancies defined by the architectural drawings and includes other information pertinent to the structural design. We recommend that the EOR review the following list for items that should also be included and addressed in the design criteria: Clearly identify the equivalent uniform partition loads used in the design (NYCBC 1603.1.1). Base shear for wind loads (NYCBC 1603.1.5). Maximum soil bearing capacity of soil under the mat foundation (NYCBC 1603.1.7). Design criteria loading of foundation walls due to static and seismic earth pressures, surcharge, and hydrostatic pressures (NYCBC 1603.1.9) Leslie E. Robertson Associates, RLLP LERA Consulting Structural Engineers P1120 – 11 Hoyt Street 11 December 2017 Structural Peer Review Report Page 2 3. Superstructure Review 3.1 Architectural and Structural Drawings We reviewed and compared the architectural drawings with structural drawings prepared by McNamara Salvia and found that the structural drawings were in general conformance with the architectural drawings. 3.2 Midas Gen Model We independently developed a global building model using Midas Gen. The latter was generated from the structural CAD drawings provided by McNamara Salvia. Elements including the foundation mat were modeled per the information found in the structural drawings. The spring stiffness of GIEs (Ground Improvement Elements) and soil under the mat which were provided by Langan were also incorporated into the mat. Gravity and earthquake loads were defined using the information provided in the structural drawings. Finally, wind loads were defined following recommendations found in the wind tunnel report by RWDI. The model was used to review the global behavior of the building, as well as to obtain loads for the design checks of some foundation and structural elements. Figure 1, below, shows different views of the Midas Gen model. Figure 1 – Global Midas Gen Model View Leslie E. Robertson Associates, RLLP LERA Consulting Structural Engineers P1120 – 11 Hoyt Street 11 December 2017 Structural Peer Review Report Page 3 3.2.1 Base Shear Check The Midas Gen model was also used to compare the building base shear from earthquake and wind loads shown on drawing S-001.01 and in the wind tunnel report respectively. We found the base shear from wind loads to be similar, but found an 8% reduction in the base shear from earthquake loads compared to the design base shear shown on drawing S-001.01. Figure 2 and 3 present the global shears and overturning moments taken from the Midas Gen model for wind and earthquake loads. (a) (b) Figure 2 – Global Model Shears (a) Wind Loads (Envelope), (b) Earthquake Loads (Envelope) (a) (b) Figure 3 – Global Model Overturning Moments (a) Wind Loads (Envelope), (b) Earthquake Loads (Enveloped) Leslie E. Robertson Associates, RLLP LERA Consulting Structural Engineers P1120 – 11 Hoyt Street 11 December 2017 Structural Peer Review Report Page 4 3.3 Load Path We reviewed typical floors, walls and columns as well as the mat foundation and GIE and found they generally seemed to be well proportioned for the size and type of building. The superstructure seems to have a continuous load path. 4. Mat Foundation 4.1 Soil Pressures The soil pressures due to gravity loads and gravity+wind loads are shown in Figure 4. The peak pressure is 14 KSF for the gravity load case and 16 KSF for wind+gravity load case. (a) (b) Figure 4 – Soil Pressures due to (a) Gravity Loads (b) Gravity+Wind Loads(Envelope) in KSF These 14 KSF and 16 KSF of pressure compare to a maximum expected pressure, as noted in the Langan report of 20 KSF. 4.2 Settlements The settlements due to gravity loads and gravity+wind loads are as shown in Figure 5, with a peak settlement of 2.16 inches for gravity case and 2.70 inches for gravity+wind case. Leslie E. Robertson Associates, RLLP LERA Consulting Structural Engineers P1120 – 11 Hoyt Street 11 December 2017 Structural Peer Review Report Page 5 (a) (b) Figure 5 – Settlements due to (a) Gravity Loads (b) Gravity+Wind Loads (Envelope) in IN 4.3 Flexural Capacity The flexural capacity of the mat foundation was reviewed using the Midas Gen model according to the information shown in drawings FO-100.00 and FO-201.00. Table 1 summarizes the DCRs of typical reinforcement in different portions of the mat foundation. For the additional reinforcement presented in drawing FO-201.00, we made some spot checks for locations indicated in Figure 6, with findings summarized in Table 2. Table 1 – Summary of Mat Foundation Flexural Capacity Check (Typical reinforcement) Mat Thickness Direction Bottom Reinforcement (DCR) Top Reinforcement (DCR) N-S #11@12 (0.54) #11@8 (-) 6’-6” NORTH E-W #11@6 (0.74) #10@12 (-) N-S #11@12 (0.95) #11@8 (0.35) 6’-6” SOUTH E-W #11@8 (0.90) #11@12 (0.54) N-S #11@6 (0.30) #11@8 (0.35) 6’-6” EAST&WEST E-W #11@6 (0.30) #11@12 (0.54) N-S #11@6 +#11@6 (0.56) #11@8 (0.56) 10’-0” E-W #11@6 +#11@6 (0.76) #11@12 (0.84) Leslie E. Robertson Associates, RLLP LERA Consulting Structural Engineers P1120 – 11 Hoyt Street 11 December 2017 Structural Peer Review Report Page 6 Figure 6 – Location of Mat Foundation Reinforcement Checks (from FO-100.00) Table 2 –Summary of Mat Foundation Flexural Capacity Check (Additional reinforcement) Location Direction Reinforcement DCR 1. 6’-6” North- NW Corner Bottom, N-S #11@6 + #11@6 (per Note7 of FO-201.00) 0.42 2. 6’-6” North- C5 Bottom, E-W #11@6 + #11@6 0.79 3. 10’-0” - Core Wall-N Bottom, N-S #11@6 + #11@6 +#11@6 + #9@12 0.90 4. 10’-0” – Core Wall-NW Top, E-W #11@12 + #10@12 0.87 5. 10’-0” – Core Wall-S Bottom, N-S #11@6 + #11@6 + #11@6 + #11@12 0.94 6. 10’-0” – Core Wall-SW Bottom, N-S #11@6 + #11@6 + #11@6 + #9@12 0.92 Bottom, E-W 11@6 + #11@6 +11@6 + #11@6 0.96 7. 10’-0” – Core Wall-SE Bottom, N-S 11@6 + #11@6 11@6 + #9@12 0.90 From the sample calculations, we believe that the flexural design of the mat foundation is adequate. Leslie E. Robertson Associates, RLLP LERA Consulting Structural Engineers P1120 – 11 Hoyt Street 11 December 2017 Structural Peer Review Report Page 7 4.4 One-Way Shear Capacity The one-way shear capacity of the mat foundation was reviewed using the information shown in drawings FO-100.00 and FO-202.00.