Materials

Steel

Steel offers a high stiffness and strength-to-weight ratio, ductility and strong seismic performance, predictable fabrication quality, speed of construction, adaptability for future modification, and a strong sustainability profile.

Core Standards

The American Institute of Steel Construction (AISC) is the primary technical organization governing structural steel design in the United States.

• AISC 360 — Specification for Structural Steel Buildings
• AISC 341 — Seismic Provisions for Structural Steel Buildings
• AISC 342 — Seismic Provisions for Evaluation and Retrofit
• AISC Code of Standard Practice — roles, responsibilities, and expectations for design, detailing, and fabrication

Design References

• Steel Construction Manual — the primary design reference
• Companion to the AISC Steel Construction Manual — a two-volume supplement
• Companion Design Examples — worked examples supplementing the Manual
• AISC Design Guides — 40+ topics including stability, ponding, serviceability, fire, and rehabilitation
• Seismic Design Manual, Facts for Steel Buildings, and archived historic standards

Many AISC documents are free, and new graduates can join AISC as an Emerging Professional at no cost for additional access.

Sustainability

• Average hot-rolled structural shapes contain roughly 92% recycled content
• All United States structural steel shapes are made in electric-arc furnaces
• Steel is 100% recyclable with no loss of quality
• Every United States mill provides facility-specific Environmental Product Declarations (EPDs)

Tools, Learning, and Bridges

AISC maintains a Steel Availability Tool for shapes, mills, and rolling schedules; a Steel Solutions Center covering seismic, fire, connections, and stability; and Ask Clark, its technical chatbot. The AISC Learning Portal and NASCC: The Steel Conference cover continuing education. For visual learners, the AISC Teaching Aids site offers a 3D model viewer, buckling mode visualizations, interactive design figures, and virtual tours of mills and fabrication shops. For bridge work, the National Steel Bridge Alliance (NSBA) publishes the Steel Bridge Design Handbook and standard plans.

Related organizations: AISC, American Iron and Steel Institute (AISI), Steel Deck Institute (SDI), Steel Joist Institute (SJI), Steel Tube Institute (STI), Steel Framing Industry Association (SFIA).

Concrete

Concrete is used in foundations, slabs, walls, cores, frames, and infrastructure for its durability, fire resistance, versatility, and compressive strength. Reinforcing steel, prestressing, and post-tensioning extend what it can do, especially in seismic regions.

Core Standards

The American Concrete Institute (ACI) publishes the codes referenced by the IBC.

• ACI 318 — Building Code Requirements for Structural Concrete, the main standard for cast-in-place and precast reinforced concrete
• ACI/PCI 319 — Structural Precast Concrete
• ACI/PTI 320 — Post-Tensioned Structural Concrete
• ACI 440.11 — Concrete Reinforced with Glass Fiber Reinforced Polymer (GFRP) Bars
• ACI 440.13 — Fiber Reinforced Polymer (FRP) Strengthening of Existing Structures
• ACI 562 — Assessment, Repair, and Rehabilitation of Existing Concrete Buildings

Design Guides

• MNL-17 — Reinforced Concrete Design Handbook
• MNL-66 — ACI Detailing Manual
• MNL-7 — GFRP-Reinforced Concrete Design Handbook
• MNL-3 — Guide to ACI 562
• SEAOC Structural/Seismic Design Manual, Volume 3 — concrete examples

ACI offers discounted membership for professionals under 28, including standards discounts, free or reduced ACI University courses, access to 200+ guides and reports, and local chapter networking.

Related organizations: ACI, International Code Council (ICC), Precast/Prestressed Concrete Institute (PCI), Post-Tensioning Institute (PTI).

Wood

Wood is widely used in low- to mid-rise buildings for its availability, ease of construction, cost, and sustainability. Engineered products — glulam, laminated veneer lumber (LVL), and cross-laminated timber (CLT) — now make long spans, tall wood buildings, and high-performance lateral systems possible.

National Design Specifications (NDS)

Wood design is governed primarily by the American Wood Council (AWC). The NDS is the foundational standard, covering:

• Material properties and species/grade design values
• Allowable Stress Design (ASD) and Load and Resistance Factor Design (LRFD) methods
• Bending, shear, compression, and tension checks
• Connection design — bolts, screws, nails, staples
• Glulam, structural composite lumber, and specialty products
• Member stability and fire considerations

A typical wood design workflow runs: determine nominal strength from material properties, apply adjustment factors, calculate factored capacity, then compare capacity to demand.

Other Key References

• SDPWS — Special Design Provisions for Wind and Seismic, required for wood shear walls, diaphragms, holddowns, collectors, and lateral detailing
• SEAOC Structural/Seismic Design Manual, Volume 2 — light-frame wood examples
• Wood Frame Construction Manual (WFCM) — prescriptive framing guidance

WoodWorks and AWC Tools

WoodWorks provides typical details for diaphragms, shear walls, collectors, and CLT, along with technical papers, design examples, mass timber guidance, and free design assistance from their engineers. AWC offers online connection calculators, commentary documents, fire design resources, and span tables.

Related organizations: AWC, APA – The Engineered Wood Association, WoodWorks.

Masonry

Masonry offers durability, fire resistance, competitive cost, and architectural flexibility. Modern masonry is typically reinforced, which provides ductility and strong seismic performance.

Masonry has more design constraints that come from how it is physically built than any other material on this page. These are the concepts that catch new engineers out.

Allowable Stress Design vs. Strength Design

Masonry may be designed using Allowable Stress Design (ASD), the legacy approach, or Strength Design (SD), the modern preferred method. Strength Design should be your default because it aligns with reinforced concrete design philosophy, is consistent with load combinations used elsewhere in the building, typically produces more rational reinforcement layouts, and reflects the direction of modern codes. ASD still appears in small projects and existing conditions.

Modularity

Economical masonry respects modular block dimensions. Standard concrete masonry unit (CMU) construction is based on an 8-inch module vertically and horizontally. When the structural grid or openings ignore that module, units must be cut, labor and waste increase, bond patterns become irregular, and costs rise. Coordinate structural grids, opening dimensions, story elevations, and control joint locations with the architect early.

If it does not land on the masonry module, it will likely cost more.

Reinforcement is Constrained by Cell Geometry

Vertical bars are placed in grout cells, spacing must align with cell centers, and bar spacing cannot be arbitrary. You cannot specify bars at 5 inches on center. Typical vertical spacings align with block modules — 8, 16, 24, or 32 inches — depending on block type and configuration. If your analysis suggests a non-modular spacing, increase bar size, reduce spacing to the next available cell, increase wall thickness, or reconsider the system. Design that ignores cell geometry is not constructible.

Arching Action and Control Joints

Masonry can self-support through arching. When designing lintels, evaluate arching first because it reduces flexural demand, and avoid placing control joints inside the arch thrust line, which disrupts the mechanism. Control joints reduce long-term cracking but affect structural performance — in high seismic regions, coordinate joint spacing with your shear wall model, since joints can significantly change wall stiffness and lateral behavior.

Existing Masonry

Existing masonry buildings fall outside the scope of TMS 402/602 and require experienced engineering judgment. Reinforcement may be unknown, materials vary, and lateral performance is often complex. Consult senior engineers or specialists.

Codes and References

TMS 402/602 — Building Code Requirements and Specification for Masonry Structures, published by The Masonry Society, is the primary masonry design code referenced by the IBC and CBC.

• SEAOC Structural/Seismic Design Manual, Volume 2 — masonry examples
• Reinforced Masonry Engineering Handbook
• Design of Reinforced Masonry Structures
• CMD21 Design Tool
• Masonry Designers’ Guide — 150+ worked examples including full building designs
• Strength Design of Masonry — overview of the SD methodology
• Masonry Education Hub — 60+ on-demand courses
• Industry tech notes: CMACN Masonry Chronicles, MIA Technical Publications, WSCPA Technical Publications, NCMA TEK Notes, BIA Tech Notes

Masonry practices vary regionally. Local masonry organizations can advise on available unit types, reinforcement practices, detailing standards, and common construction limitations.

Related organizations: Concrete Masonry Association of California and Nevada (CMACN), Masonry Institute of America (MIA), Western States Clay Products Association (WSCPA), The Masonry Society (TMS), Concrete Masonry and Hardscapes Association (CMHA, formerly NCMA), International Masonry Institute (IMI).

Cold-Formed Steel

Cold-formed steel (CFS), often called light-gauge steel, is lightweight, strong, dimensionally stable, non-combustible, and well suited to prefabrication. Its high strength-to-weight ratio makes it efficient for repetitive framing and modular construction.

Common applications include infill walls in steel and concrete frames, roof and floor framing, mid-rise load-bearing buildings, and lateral systems such as steel sheet shear walls.

Core Standards

CFS design is governed by the American Iron and Steel Institute (AISI).

• AISI S100 — North American Specification for the Design of Cold-Formed Steel Structural Members; the primary standard for columns, studs, joists, headers, and tracks
• AISI S240 — North American Standard for Cold-Formed Steel Structural Framing, covering load-bearing and non-structural framing
• AISI S400 — Seismic Design Standard, required in seismic regions for steel sheet shear walls, strap braced walls, collectors, and boundary elements
• AISI S220 — Nonstructural Framing Standard, for interior partitions and non-load-bearing walls

Design Guides

• Cold-Formed Steel Design Manual
• Cold-Formed Steel Engineers Institute design guides
• AISI design resources and Steel Framing Industry Association resources
• SEAOC Structural/Seismic Design Manual, Volume 2 — CFS shear wall and diaphragm examples
• Diaphragm Design Manual, Steel Deck on Cold-Formed Steel Framing Design Manual, Floor Deck Design Manual, Roof Deck Design Manual

Related organizations: AISI, Cold-Formed Steel Engineers Institute (CFSEI), Steel Framing Industry Association (SFIA).