Architect Registration Examination Changed Project-Planning-Design Questions

Comprehensive and Detailed Explanation From Exact Extract:

In seismic design, vertical irregularities are discontinuities or abrupt changes in the building’s mass, stiffness, or geometry that can affect seismic response and increase vulnerability during an earthquake. The NCARB ARE 5.0 Project Planning & Design guidelines describe vertical irregularities as changes occurring along the height of the building.

Option C describes a mass irregularity where story 2 has twice the effective mass of story 1. According to seismic code provisions (such as those referenced in ASCE 7 and adopted by IBC), a vertical mass irregularity is present if the effective seismic mass in any story is more than 150% (1.5 times) or less than 70% (0.7 times) of the mass of an adjacent story. Here, doubling the mass is a significant vertical irregularity that affects the dynamic behavior and design.

Option A, the roof mass being half that of the floor below, is a decrease in mass but less than the typical threshold of 30% difference (the ratio is 0.5, which is a 50% difference). This might also be considered, but the mass irregularity is more typically flagged at the 1.5x or 0.7x threshold and tends to be more critical in lower floors, making C the clearer choice.

Option B describes a reentrant corner, which is a horizontal plan irregularity, not vertical. Reentrant corners affect torsional behavior but are not classified as vertical irregularities.

Option D refers to stiffness differences between interior shear walls and perimeter columns but, when symmetrically placed, this is not necessarily considered an irregularity. Vertical stiffness irregularities are defined by abrupt stiffness changes in vertical elements, but symmetry mitigates torsional effects.

The presence of vertical mass irregularities significantly influences seismic forces distribution, dynamic response, and the potential for torsional motions. Designers must recognize these irregularities per NCARB guidelines and apply appropriate structural detailing and design modifications to meet life-safety requirements.

Comprehensive and Detailed Explanation From Exact Extract:

A raised access floor system provides a flexible, accessible space beneath the finished floor for routing power, data, telecommunications, and security cables. It facilitates easy reconfiguration and tenant fit-out modifications without major disruption.

Poke-through systems (A) provide limited point access for power/data and are less flexible for extensive rewiring.

Cellular deck systems (B) are structural components, not distribution systems.

Flat cable wiring (D) is a wiring method but does not provide the physical infrastructure for flexibility.

Comprehensive and Detailed Explanation From Exact Extract:

Reducing embodied energy involves strategies that minimize new material production and transportation impacts:

Re-using existing buildings (A) avoids new material consumption and demolition waste.

Using local and low-energy materials (C) reduces transportation energy and energy-intensive materials.

Simple geometric structures (F) use fewer materials and minimize complexity, lowering embodied energy.

Orientation and transitional spaces (B) mainly affect operational energy, not embodied energy.

Altering the proportion of high-rise or single-story units (D, E) affects land use and operational efficiency more than embodied energy.

NCARB emphasizes these strategies in sustainable design practices.

Comprehensive and Detailed Explanation From Exact Extract:

When a building’s size and occupancy cause non-compliance with allowable building area or frontage requirements, the architect should first check frontage area increase provisions allowed by the code. The frontage increase can allow a larger building area based on the length of street frontage and fire access, especially when sprinklers and fire lanes are provided.

Adding firewalls (A) is a method to subdivide building area but is typically considered after exploring frontage increases.

Reducing building area (C) is a last resort if other allowances are insufficient.

Therefore, the architect should first verify if frontage area increases resolve the compliance issue.