Plan Review: 52 Issues Found

Summary: The Grade 80 Beam and Girder Tension Development and Lap Splice Length table (Detail 8) shows values that are identical to the Grade 60 table (Detail 5) for every bar size, lap class, concrete strength, and bar position. For example, a #8 bottom bar Class A splice at f'c = 3000 PSI is shown as 56" in both the Grade 60 and Grade 80 tables. Per ACI 318-19 Section 25.4.2.1, development length is c...

Why it matters: Using these incorrect (undersized) development and splice lengths for Grade 80 reinforcement would result in bars that are not adequately developed, directly compromising structural capacity and load path integrity. This could lead to bond failures, particularly at critical sections in beams and ...

Suggested next step: Request the structural engineer verify and recalculate the Grade 80 Beam and Girder Tension Development and Lap Splice Length table (Detail 8) using the correct yield strength (fy = 80,000 psi) and applicable ACI 318-19 Section 25.4.2 provisions, including the reinforcement gr...

RFI draft: Request the structural engineer verify and recalculate the Grade 80 Beam and Girder Tension Development and Lap Splice Length table (Detail 8) using the correct yield strength (fy = 80,000 psi) and applicable ACI 318-19 Section 25.4.2 provisions, ...

Summary: The GRAVITY LOAD KEY LEGEND specifies that for the ELECTRICAL ROOM CEILING, the concentrated live load of 2 kips "DOES NOT NEED TO BE CONSIDERED CONCURRENTLY WITH 20 PSF SDL" (Superimposed Dead Load). However, ACI 318-19 Section 5.3.1 and Table 5.3.1 require the required strength (U) to be calculated using load combinations that always include Dead Load (D) concurrently with Live Load (L), such...

Why it matters: Excluding the 20 PSF superimposed dead load from the load combination when designing for the 2 kip concentrated live load will result in under-designed structural beams, potentially leading to structural failure. This contradicts fundamental building code load combination equations.

Suggested next step: Please clarify if the note intended to state that the concentrated live load does not need to be considered concurrently with the 20 PSF uniform live load, rather than the 20 PSF Superimposed Dead Load (SDL). Update the drawing to ensure all dead loads are included in load com...

RFI draft: Please clarify if the note intended to state that the concentrated live load does not need to be considered concurrently with the 20 PSF uniform live load, rather than the 20 PSF Superimposed Dead Load (SDL). Update the drawing to ensure all dead ...

Summary: The drawing specifies the rain intensity as '60-min Duration: 10 in/hr' for rain load design. ASCE 7-22 Section 8.2 explicitly requires the hydraulic head to be based on 'a rainfall intensity equal to or greater than the 15 min duration storm with return period (frequency) given in Table 8.2-1.' Furthermore, Table 8.2-1 requires a 500-year return period for Risk Category IV buildings, which thi...

Why it matters: Using a 60-minute duration rainfall intensity instead of the code-required 15-minute duration will result in substantially underestimated rain loads. This affects the structural design of the roof framing and the sizing of the secondary drainage system for structural loading (SDSL). For a Risk Ca...

Suggested next step: Request the Structural Engineer confirm the rainfall intensity used for rain load design. ASCE 7-22 Section 8.2 requires the hydraulic head to be based on a rainfall intensity equal to or greater than the 15-minute duration storm with the 500-year return period required by Tab...

RFI draft: Request the Structural Engineer confirm the rainfall intensity used for rain load design. ASCE 7-22 Section 8.2 requires the hydraulic head to be based on a rainfall intensity equal to or greater than the 15-minute duration storm with the 500-year...

Summary: The drawing explicitly specifies Seismic Design Category D with 'Steel ordinary moment frames' (R=3.5) and 'Steel Ordinary Braced Frames' (R=3.25) as the basic seismic force-resisting systems. IBC Section 2202.2.1.2 requires that structures assigned to Seismic Design Category D, E, or F 'shall be designed and detailed in accordance with AISC 341, except as permitted in ASCE 7, Table 15.4-1.' Pe...

Why it matters: This is a fundamental design error affecting the entire lateral force-resisting system. A Risk Category IV structure in SDC D requires higher-ductility systems such as Special Moment Frames (R=8), Special Concentrically Braced Frames (R=6), Buckling-Restrained Braced Frames (R=8), or other system...

Suggested next step: Request that the Structural Engineer revise the seismic force-resisting system to one permitted for Seismic Design Category D per IBC Section 2202.2.1.2 and ASCE 7 Table 12.2-1 (e.g., Special Moment Frames, Special Concentrically Braced Frames, Eccentrically Braced Frames, or ...

RFI draft: Request that the Structural Engineer revise the seismic force-resisting system to one permitted for Seismic Design Category D per IBC Section 2202.2.1.2 and ASCE 7 Table 12.2-1 (e.g., Special Moment Frames, Special Concentrically Braced Frames, Ec...

Summary: The Grade 80 beam and girder tension development and lap splice length table lists values that are identical to the Grade 60 table for every bar size (#8 through #11) and every concrete strength (3000, 4000, 5000, and 6000 PSI). For example, a #8 bar at f'c = 3000 PSI shows Class A Bottom = 56" and Other = 73" in both the Grade 60 and Grade 80 tables. Per ACI 318, which is mandated by IBC Secti...

Why it matters: Using these unconservative development and lap splice lengths for Grade 80 reinforcement means bars would not be adequately developed or spliced, risking bond failure and potential structural collapse. This error is critical for any beam or girder designed with Grade 80 reinforcement. If caught d...

Suggested next step: Request that the structural engineer recalculate and issue a corrected Grade 80 beam and girder tension development and lap splice length table using the appropriate yield strength (fy = 80,000 psi) per ACI 318. All values must be recalculated; the current table values are ide...

RFI draft: Request that the structural engineer recalculate and issue a corrected Grade 80 beam and girder tension development and lap splice length table using the appropriate yield strength (fy = 80,000 psi) per ACI 318. All values must be recalculated; th...

Summary: S-70300 Detail 14 illustrates typical beam penetrations and refers to 'SCHEDULED BEAM REINFORCEMENT'. When determining development lengths for these beams using S-00500, the schedule for 'GRADE 80 REINFORCEMENT' provides lap lengths that are exactly identical to the 'GRADE 60 REINFORCEMENT' schedule (e.g., a #8 bar Class A bottom bar is 49" in both tables). Since Grade 80 steel has a higher yie...

Why it matters: Utilizing Grade 60 lap splice lengths for Grade 80 reinforcement will result in severely undersized splices that cannot develop the full yield strength of the rebar. This is a critical structural safety deficiency that violates building code requirements and could lead to structural failure if Gr...

Suggested next step: Please revise the 'BEAM AND GIRDER TENSION DEVELOPMENT AND LAP SPLICE LENGTHS GRADE 80 REINFORCEMENT' schedule on S-00500 to provide the correct, longer development lengths required for Grade 80 steel.

RFI draft: Please revise the 'BEAM AND GIRDER TENSION DEVELOPMENT AND LAP SPLICE LENGTHS GRADE 80 REINFORCEMENT' schedule on S-00500 to provide the correct, longer development lengths required for Grade 80 steel.

Summary: The drawings contradict each other regarding the architectural envelope and structural framing of the Electrical Rooms located between Grids C and D. The S-01000 'ROOF LEVEL LOAD PLAN' shows the main 'DATA CENTER ROOF' extending across the entire footprint from Grid A to Grid D, which places the Electrical Rooms inside the main building under the main roof. However, the S-20208 framing plan spe...

Why it matters: If the Electrical Room lid is a separate exterior stepped roof (as supported by the framing plans and roofing callouts), it is exposed to the environment and requires a structural snow load and snow drift criteria due to the elevation step at Grid C. The S-01000 load legend fails to provide a sno...

Suggested next step: Please clarify the building envelope at the Electrical Rooms. Are the Electrical Rooms enclosed under the main Data Center Roof (as shown on the S-01000 Roof Level Load Plan), or are they a separate exterior stepped lean-to structure? If they are a stepped exterior structure, ...

RFI draft: Please clarify the building envelope at the Electrical Rooms. Are the Electrical Rooms enclosed under the main Data Center Roof (as shown on the S-01000 Roof Level Load Plan), or are they a separate exterior stepped lean-to structure? If they are ...

Summary: The Overall Structural Framing Plan (S-20200) indicates a clear-span layout, detailing column symbols only along exterior grids A and D, with an open framing layout between grids A and C. In direct contradiction, Building Section 3 (S-40100) depicts a multi-span PEMB frame featuring intermediate column supports. Specifically, the section details an interior structural column at Grid B resting o...

Why it matters: This discrepancy creates a severe structural conflict for the Pre-Engineered Metal Building (PEMB) manufacturer and foundation trades. A multi-span frame requires interior columns and corresponding interior spread footings (which are missing from the framing plan). Conversely, a clear-span frame ...

Suggested next step: Please clarify the PEMB rigid frame design intent. Section 3 (S-40100) shows an intermediate interior column at Grid B with its own foundation footing, while the Overall Framing Plan (S-20200) indicates columns only along exterior Grids A and D, implying a clear-span frame. Ar...

RFI draft: Please clarify the PEMB rigid frame design intent. Section 3 (S-40100) shows an intermediate interior column at Grid B with its own foundation footing, while the Overall Framing Plan (S-20200) indicates columns only along exterior Grids A and D, i...

Summary: The Gravity Load Key Legend on the drawing specifies a flat roof snow load of Pf = 30 PSF for both the Administration Roof and the Data Center Roof. However, the Structural General Notes on sheet S-00100 explicitly state the flat-roof snow load (Pf) as 40 PSF. The drawing's Note 3 explains that the 30 PSF value corresponds to a maximum ground snow load of 40 PSF (i.e., it appears to be a calcul...

Why it matters: A 25% reduction in the design flat roof snow load (30 PSF vs. 40 PSF) could result in under-designed roof framing members, connections, and columns. For a Risk Category IV structure, this discrepancy is particularly critical as the building is classified as essential and must remain operational. ...

Suggested next step: Request clarification from the Structural Engineer of Record on the correct flat roof snow load (Pf) to be used for design. The Structural General Notes state Pf = 40 PSF, while the Gravity Load Key Legend on S-01000 shows Pf = 30 PSF. Confirm which value governs and whether t...

RFI draft: Request clarification from the Structural Engineer of Record on the correct flat roof snow load (Pf) to be used for design. The Structural General Notes state Pf = 40 PSF, while the Gravity Load Key Legend on S-01000 shows Pf = 30 PSF. Confirm whi...

Summary: The Grade 80 Beam and Girder Tension Development and Lap Splice Lengths table (Detail 8) lists development and lap splice lengths for bar sizes #8 through #11 that are exactly identical to the values shown in the Grade 60 table (Detail 5). For example, at f'c = 3000 PSI, the #8 bar Class A values are Bottom = 56" and Other = 73" in both tables; the #9 bar Class A values are Bottom = 66" and Oth...

Why it matters: If contractors use these incorrect Grade 80 development and lap splice lengths during construction, all Grade 80 reinforcing bar splices and development lengths in beams and girders would be undersized by approximately 33% or more, resulting in bars that are not fully developed. This could lead t...

Suggested next step: Request the structural engineer to review and correct the Grade 80 Beam and Girder Tension Development and Lap Splice Lengths table (Detail 8) with properly calculated values for Grade 80 reinforcement per ACI 318. Confirm whether the current values were erroneously copied fro...

RFI draft: Request the structural engineer to review and correct the Grade 80 Beam and Girder Tension Development and Lap Splice Lengths table (Detail 8) with properly calculated values for Grade 80 reinforcement per ACI 318. Confirm whether the current valu...

Summary: The drawing depicts a building significantly larger than the maximum parameters specified in the seismic design criteria. The structural framing plan for Sector 06 spans vertical grid lines 19 through 29, covering approximately 227 feet of length (demonstrated by the 25'-0", 24'-7", and 2'-8" bay dimensions). The associated keyplan indicates the building is composed of 14 sectors arranged in a ...

Why it matters: If the actual constructed structure is over 1,500 feet long, the seismic base shear and total building weight (W = 2415 kips) calculated for a 630-foot building in the general notes are critically undersized. This discrepancy will lead to a severely under-designed lateral-force resisting system a...

Suggested next step: Please clarify the actual building dimensions. Update the seismic design criteria in the Structural General Notes to reflect the correct building weight and base shear for the full structure shown in the keyplan, or revise the framing plans if the 630 ft x 130 ft dimension is ...

RFI draft: Please clarify the actual building dimensions. Update the seismic design criteria in the Structural General Notes to reflect the correct building weight and base shear for the full structure shown in the keyplan, or revise the framing plans if the...

Summary: The structural foundation plan specifies an '8" THICK SLAB ON GRADE. REF S-20100 FOR REINFORCEMENT' and includes a 'PEMB BRACE', indicating the slab transmits lateral forces. However, the drawings also specify a 'SAWCUT JOINT, TYP' in this slab. ACI 318-19 Section R13.2.4 states that slabs-on-ground often act as diaphragms to hold the building together and that construction documents should exp...

Why it matters: Sawcutting a structural slab creates a weakened plane that reduces its capacity to act as a continuous diaphragm. This can prevent the safe transfer of lateral forces from the PEMB brace and wind girts to the ground, potentially causing localized failure or unacceptable displacement during seismi...

Suggested next step: Please confirm if the 8" slab-on-ground is designed to act as a structural diaphragm or to transmit lateral forces. If so, please remove the sawcut joint details and specify appropriate construction joints that maintain structural continuity, as per ACI 318-19 R13.2.4.

RFI draft: Please confirm if the 8" slab-on-ground is designed to act as a structural diaphragm or to transmit lateral forces. If so, please remove the sawcut joint details and specify appropriate construction joints that maintain structural continuity, as p...

Summary: Detail 7 ("TYPICAL WIDENED CONCRETE BEAM") shows transverse U-bar ties labeled "#3@12\" UNLESS NOTED OTHERWISE IN DETAILS (NOT SCHEDULED)" connecting the widened section to the main beam. The inner ends of these U-bars, located inside the "SCHEDULED BEAM WIDTH", are detailed with 90-degree standard hooks that terminate directly into the concrete without enclosing any longitudinal reinforcement....

Why it matters: Standard hooks used for transverse reinforcement that fail to enclose longitudinal bars lack proper mechanical anchorage. When the ties are stressed in tension or shear, these unanchored hooks can straighten, causing the surrounding cover concrete to spall. This compromises the structural integri...

Suggested next step: Please revise Detail 7 to ensure that the inner standard hooks of the #3 transverse ties enclose the existing "SCHEDULED BEAM REINFORCEMENT" or provide additional longitudinal bars at the inner hook locations to comply with ACI 318 anchorage requirements.

RFI draft: Please revise Detail 7 to ensure that the inner standard hooks of the #3 transverse ties enclose the existing "SCHEDULED BEAM REINFORCEMENT" or provide additional longitudinal bars at the inner hook locations to comply with ACI 318 anchorage requi...

Summary: The Gravity Load Key Legend for the Electrical Room Ceiling states: 'CONCENTRATED LOAD DOES NOT NEED TO BE CONSIDERED CONCURRENTLY WITH 20 PSF SDL.' The 20 PSF SDL is explicitly classified as Superimposed Dead Load in the legend column. Per IBC Section 1606.1, buildings and parts thereof shall be designed to resist the effects of dead loads. Furthermore, IBC Section 1605.2 load combinations (e....

Why it matters: If the combined case of full dead load (self-weight + 5 PSF deck/roofing + 20 PSF SDL) plus the 2 kip concentrated live load produces higher beam forces than either the uniform load case alone or the concentrated load case without the 20 PSF SDL, the resulting beam sizes could be inadequate. This...

Suggested next step: Confirm that all beams supporting the Electrical Room Ceiling are designed for the combined case of full dead load (including the 20 PSF superimposed dead load) plus the 2 kip concentrated live load, in addition to the uniform live load case. Revise the Gravity Load Key Legend...

RFI draft: Confirm that all beams supporting the Electrical Room Ceiling are designed for the combined case of full dead load (including the 20 PSF superimposed dead load) plus the 2 kip concentrated live load, in addition to the uniform live load case. Revi...

Summary: The "CLASS OF CONCRETE MATRIX" schedule identifies "EXTERIOR SLABS-ON-GRADE" with an exposure class of "F1" (indicating exposure to freezing and thawing). However, the schedule lists the "PERMISSIBLE AIR CONTENT (%)" for this mix as "N/A". According to IBC Section 1907.2, nonstructural slabs-on-ground must comply with Section 1904.2, which mandates that nonstructural concrete with a freeze-thaw...

Why it matters: If the contractor relies on the "N/A" designation in the matrix and orders non-air-entrained concrete for exterior flatwork in a freeze-thaw environment, the slabs will lack essential durability. This will lead to rapid deterioration, spalling, and scaling of the exterior concrete during winter m...

Suggested next step: The Concrete Matrix schedule specifies "N/A" for the permissible air content of exterior slabs-on-grade, despite correctly assigning an F1 exposure class. Please provide the required air entrainment percentage range for this mix to comply with the freeze-thaw durability requir...

RFI draft: The Concrete Matrix schedule specifies "N/A" for the permissible air content of exterior slabs-on-grade, despite correctly assigning an F1 exposure class. Please provide the required air entrainment percentage range for this mix to comply with the...