High-Rise Structural: 77 Issues Found
A comprehensive structural plan review of a 25-story coastal high-rise uncovered 77 issues—including outdated seismic standards, insufficient partition loads, and critical live load violations—before permit submission.
The Project
A 25-story high-rise residential development on the Texas coast. InspectMind performed a comprehensive structural plan review, identifying critical seismic design issues (ASCE 7-10 used instead of required ASCE 7-16), partition load violations (10 PSF instead of code-required 15 PSF), and live load conflicts for elevator machine rooms before permit submission.
Critical Findings (25)
The drawing states the project is based on the '2021 International Building Code' but then specifies that 'Seismic loads are based on the American Society of Civil Engineers ASCE 7-10.' The 2021 IBC requires seismic design to be in accordance with ASCE 7-16, not ASCE 7-10. This is a direct inconsistency between the stated governing code and the seismic design standard being used.
The drawing explicitly states that partition loads are designed using 'An allowance of 10 PSF or the actual weight of the wall, whichever is greater.' However, Section 1607.5 of the 2021 IBC requires that 'The partition load shall be not less than a uniformly distributed live load of 15 psf.' The specified 10 PSF allowance is 33% below the code-mandated minimum of 15 PSF.
The drawing states design live load of 40 PSF for the Framing Plan of Elevator Machine Room and Roof Level. The specification requires Elevator Machine Rooms to be designed for 125 PSF live load. The drawing's stated 40 PSF is less than one-third of the required 125 PSF load.
The drawing shows a design live load of 40 PSF for the Terrace Level (LVL 23). The General Notes specification requires a live load of 100 PSF for 'Assembly Areas, Plazas, Terraces, Lobbies' per the live load design criteria table. The drawing value of 40 PSF is less than half the required value.
IBC Section 1603.1 requires that construction documents show the "relative locations of structural members" with "offsets dimensioned." The provided framing plan (Sheet S103) displays several shear wall cores (e.g., W1/W2/W9/W10) and columns but fails to provide specific dimensions locating these elements relative to the established grid lines (A-I, 1-6). For example, the core bounded by walls W1, W2, W9, and W10 has no dimensions locating it horizontally or vertically relative to the adjacent grids 3, 4, A, or B. Without these dimensions, the structural elements cannot be accurately located or constructed.
Sample High Priority Findings (25 Total)
The Typical Grade Beam "T" Intersection Detail (Detail 5) shows a dimension of "1" CLEAR" at the grade beam edge. The specification requires reinforcement cover for grade beams of 1-1/2" top, 3" bottom, and 2" for formed sides. For earth-formed grade beam sides, a minimum 3" side cover is required. The drawing's 1" clear dimension does not meet any of these cover requirements.
The General Notes require material substitutions to be approved by the "International Conference of Building Officials (ICBO)" and require an "ICBO report". The ICBO ceased operations in 2003 when it merged to form the ICC. Consequently, valid "ICBO reports" are no longer issued for new products. This requirement conflicts with IBC Section 1703.4.2, which allows research reports from any "approved source" (such as ICC-ES).
The drawing specifies a concentrated load of 2000 lb for 'Garages – Private Car.' However, Section 1607.7 of the 2021 IBC requires 'For garages restricted to passenger vehicles accommodating not more than nine passengers, 3,000 pounds (13.35 kN) acting on an area of 4.5 inches by 4.5 inches.' The specified concentrated load is 33% below the code requirement.
The lap splice lengths specified in Detail 6 for #4, #5, and #6 bars (at f'c = 3000 psi) are shorter than the minimum development lengths required by ACI 318. For example, in Detail 6 (Category 1), a #5 bar is listed with a lap of 21 inches. Using the ACI 318 Simplified Method for Grade 60, f'c=3000, normalweight concrete, the minimum required development length is approximately 27.4 inches ($43.8d_b$). The listed value of 21 inches represents a deficiency of ~23%. Similarly, the #4 bar listed at 17 inches is below the required ~21.9 inches.
Detail 2 specifies 1 1/2" and 2" cover for foundation walls but fails to specify the 3" cover requirement for concrete cast against and permanently exposed to earth (ACI 318 requirement). While adjacent Details 1 and 3 explicitly list 'EARTH-FORMED' (3") and 'BOARD-FORMED' (2") options, Detail 2 omits the earth-formed condition. If a foundation wall is cast against earth using the 1 1/2" or 2" cover shown, it will violate the building code.
IBC Section 1603.1.1 mandates that the "Use of live load reduction in accordance with Section 1607.12 shall be indicated for each type of live load used in the design." The Design Loads note on Sheet S103 lists live loads (40 PSF General, 100 PSF Corridor) but fails to indicate whether live load reduction has been applied. This is a mandatory documentation requirement to establish the design basis.
The drawing states the superimposed dead load as 30 PSF including partitions. However, the specification defines minimum allowances that must be included: 10 PSF for partitions, 10 PSF for floor finishes, 5 PSF for hanging ceiling loads, and 10 PSF for mechanical equipment loads, totaling 35 PSF minimum. The drawing shows 5 PSF less than the specification requires.
The General Notes (Note 7) define sizes for "CORE BEAMS" B1, B2, and B3. However, the Structural Framing Plan does not show, label, or dimension the relative locations of these beams within the core areas or elsewhere. The contractor cannot identify where these members are to be installed.
The 'Additional Dowel Schedule' and Detail 1 specify 'Smooth Bar Dowels' to bridge the control joint but fail to specify the required material grade (e.g., ASTM A36, A615 Grade 60). IBC 1901.5 Item 2 requires construction documents to show 'The specified strength or grade of reinforcement.' Smooth bars are often available in lower grades (e.g., 36 ksi) compared to typical deformed reinforcing bars (60 ksi). Without a specified grade, the shear transfer capacity of the joint cannot be verified and may be inadequate if the contractor supplies lower-strength steel.
The plan depicts a 12" thick concrete retaining wall, which is a structural element designed to resist lateral soil loads. However, the 'Design Loads' section only lists Superimposed Dead Load and Live Load (gravity loads). It omits the lateral soil pressure (H) required for the design of these walls. IBC 1603.1 requires all pertinent design loads to be indicated, and IBC 1610.1 requires retaining walls to be designed for these soil loads.
Issue Categories
Structural
Structural issues found during plan review
Value Delivered
"The outdated seismic design standard alone would have required complete re-analysis of the entire structure. Finding 77 structural issues—including 25 critical—before submission saved us from months of redesign and permit rejection."
— Project Team, High-Rise Development