BTEH REVIEWER

Heavy Timber Framing

A traditional wood construction method using large, solid timbers joined with pegs or intricate joinery.

Heavy Timber Framing Member Dimensions

Sawn timbers or glulams typically 6–10 inches thick or larger.

Heavy Timber vs. Light-Frame Differences

Heavy Timber uses large, widely spaced members (6–10+ inches thick) with traditional joinery, while Light-Frame uses smaller, closely spaced members (< 4 inches thick) joined by nails, screws, or metal fasteners.

Mill Construction

A heavy timber system characterized by a robust timber frame integrated within load-bearing exterior masonry walls.

Mill Construction Lateral Force Resistance

Lateral resistance achieved through substantial and rigid exterior masonry walls that resist forces like wind, while the timber frame manages vertical gravity loads.

Heavy Timber Fire Resistance ('Slow-Burning' Advantage)

The tendency of heavy timbers to char on the outside, forming an insulating layer that protects the structural core.

Braced Timber Frame

A self-supporting heavy timber system relying on internal diagonal bracing for structural stability.

Inclined (Knee) Braces

Diagonal timbers forming rigid triangles within a frame to prevent racking and transfer lateral forces.

Type IV-HT Construction Alignment

Alignment with modern codes requiring noncombustible exterior walls and solid timber framing without concealed spaces.

Braced Timber Frame Bents

Primary structural components consisting of semi-rigid wood frames representing a cross-sectional slice of the building.

Sill Beams

Beams that connect posts at the foundation level.

Floor Beams (Girts)

Beams that connect posts at each floor level.

Roof Beams (Plates)

Beams that connect the tops of bents.

Purlin & Rafter System

A roof framing system where horizontal purlins span between principal rafters to directly support roof decking.

Wattle and Daub

A traditional wall infill made of woven branches plastered with clay, sand, straw, and horsehair.

Clapboard

Horizontal, overlapping wood boards nailed to studs or infill to provide weather protection.

Early Heavy Timber Forms & Evolution

Construction that evolved from basic methods using readily available materials and simple joinery.

Heavy Timber Material Composition

Utilizes large sawn timbers or glulams.

Mill Construction Primary Applications

Industrial buildings (factories, mills), commercial, institutional, and large storage buildings requiring durability and longevity.

Mill Construction Key Qualities

Durability, fire resilience, and adaptability.

Braced Timber Frame Structural Principles

A self-supporting structure where vertical and horizontal loads are carried by large timber posts and beams, allowing for flexible cladding and large openings.

Braced Timber Frame Building Applications

Predominantly 1-2 story buildings like residences, barns, and small commercial buildings (shops, taverns, workshops).

Assembly of Longitudinal Connections

The structural process of joining bents to form a stable, three-dimensional structure using sill beams, floor beams (girts), and roof beams (plates).

Roof Framing Rafter Connection

Rafters meet at the peak, connecting directly to each other without a central ridge beam.

Braced Timber Frame Erection Sequence

Step 1: Ground assembly of bents; Step 2: The raising event; Step 3: Interlocking connections using girts, plates, and joists secured with wooden pegs.

Wattle and Daub Insulation Role

Provides insulation and weather protection within timber frame infill.

Brick Masonry Infill Purpose

Used within timber frames for greater durability and fire resistance.

Mortise-and-Tenon Joint

The cornerstone timber joint where a protruding tenon fits precisely into a corresponding mortise hole.

Drawboring with Wooden Pegs

Driving wooden pegs through offset holes to pull a joint tight and enhance tensile strength.

Type IV Construction Requirements

Building code parameters specifying non-combustible exterior walls (minimum 2-hour fire rating), no concealed spaces, and minimum nominal lumber dimensions.

Type IV Minimum Column Dimension

Minimum nominal size of 8x8 inches for columns.

Type IV Minimum Floor Beam Dimension

Minimum nominal size of 6x10 inches for floor beams.

Structural Insulated Panels (SIPs)

Advanced building envelope components featuring an insulating foam core sandwiched between structural facings (OSB).

Integrated Shear Walls

Rigid walls sheathed with engineered wood used for modern lateral load resistance in timber construction.

Modern Lateral Load Systems for Timber

Integrated shear walls, rigid moment-resisting frames, mass timber elements (CLT/Glulam), and engineered steel connections.

Type IV vs. Type V Code Classification

Type IV mandates non-combustible exterior walls and strict minimum nominal timber dimensions, whereas Type V allows combustible exterior walls and has no specific fire-based minimums for general framing.

Mortise-and-Tenon Absence of Metal Hardware

Sophisticated joinery developed due to the historical lack of reliable metal connection hardware.

Wedges in Timber Joinery

Tapered pieces driven into cuts to expand timber, forcing a tighter fit against shrinkage.

Core Joinery Principles

Integrity, precision, and resilience.

Contemporary Heavy Timber Aesthetic Appeal

Exposed structural members (sawn timbers or glulam) that create strong, natural, inviting spaces.

Contemporary Heavy Timber Key Advantages

Sustainability, durability, energy efficiency, design flexibility, and faster erection.

SIP Monolithic Envelope Function

Minimizes thermal breaks, leading to superior energy efficiency and a stable indoor climate.

Rigid Frames in Timber

Moment-resisting joints that transfer bending forces for lateral resistance.

Mass Timber Elements

Cross-laminated timber (CLT) or Glulam panels used as structural walls or diaphragms.

Engineered Steel Connections in Timber

Precision-made, often hidden steel connectors used for superior strength and precision.

Engineered Lumber (Glulam) Sustainability Benefits

Provides better performance, higher strength-to-weight ratios, greater dimensional stability, and optimizes wood resources.

Steel Detailer's Role

Transforming design drawings into precise, fabrication-ready shop drawings and instructions.

Steel Shop Drawings

Detailed manufacturing blueprints providing dimensions, hole locations, weld details, and camber requirements.

Detailer's Shop Drawing Details

Specifications providing dimensions & geometry, holes & connections, weld details, and camber requirements.

Steel Fabrication Key Aspects

Operations including material ordering, automated operations (shearing, sawing, CNC drilling/punching), controlled welding, and surface preparation (cleaning, blasting, priming).

Steel Erection Drawings

On-site assembly guides indicating member positions, connection details, and safe erection sequences.

Steel Erection Key Steps

Sequence including column anchorage, leveling & plumbing, beam placement, and forced alignment.

Grid Definition & Orientation

The foundation of a framing system that defines column lines and member orientation for efficient spanning and load support.

Steel Load Flow Path

The path where loads move from deck panels, to secondary beams, to primary girders, and down through columns to the foundations.

Tertiary Framing Elements

Deck panels that directly support the floor or roof finish.

Secondary Framing Elements

Beams (joists) that collect structural loads from deck panels.

Primary Framing Elements

Girders that receive loads from secondary beams and transfer them directly to columns.

Pin-Connected Frames (Shear Connection)

Frame systems using simple connections that transfer vertical loads and allow beam rotation, relying on separate bracing for lateral stability.

Rigid Frames (Moment Connection)

Frame systems using fixed connections that prevent rotation and transfer both shear forces and bending moments.

X-Bracing (Cross Bracing)

An efficient diagonal bracing system forming an "X" shape that creates stable triangular geometries and resists tension and compression.

K-Bracing (Eccentric Bracing)

A bracing system for multistory buildings with openings where braces leave a small beam length unbraced, offering ductility recommended for seismic areas.

Steel Shear Walls

Vertical plate elements acting as large cantilever beams to resist lateral loads through shear deformation.

Diaphragm Action

The behavior of floor and roof planes acting as horizontal beams to distribute lateral forces to vertical resisting elements.

Steel Prefabrication Off-site Efficiency

Components made in controlled factories, minimizing site work and weather delays.

Steel Prefabrication Precision & Speed

High precision and rapid production leading to faster on-site erection.

Steel Fabrication Stage

Raw steel is cut, shaped, and welded into precise components based on shop drawings.

Steel Erection Stage

Transporting and assembling fabricated components on-site to form the building's frame.

Architect's Integrated Role in Steel Framing

Integrating structural and non-structural elements (HVAC, aesthetics) through early collaboration with engineers.

Detailed Plan Views

Plan drawings showing the structural system for each floor and the roof, depicting variations in member sizes or arrangement.

Multi-tiered Framing System Alternatives

1) W-sections for both primary and secondary; 2) W-sections for primary, steel joists for secondary; 3) Steel joist girders/trusses for primary, steel joists for secondary; 4) Secondary elements omitted with roof deck directly on primary elements in load-bearing wall buildings.

Steel Frame Structural Evolution

Shift from simple post-and-beam timber to modern steel frames offering superior strength-to-weight ratios, ductility, and larger clear spans.

Wind and Seismic Forces

Lateral forces that steel structures must effectively resist to prevent sway and deformation.

Mechanisms for Steel Frame Stability

Inherent stiffness of moment-resisting frames, bracing systems, or shear walls.

X-Bracing Tension Action

Diagonal members strong in tension where only one brace is active at a time under lateral load.

K-Bracing Gravity Load Benefit

Carries gravity loads on the beam, reducing the required beam size.