About

Peggi L. Clouston is a professor in the Department of Environmental Conservation at the University of Massachusetts Amherst, specializing in wood mechanics and timber engineering within the Building and Construction Technology program. She has over 30 years of experience in the field of timber engineering and conducts research on the structural behavior and efficient use of advanced bio-based composite materials, including wood, grass, and straw. Her current research topics include cross-laminated timber (CLT) panels from low-value eastern species, timber-concrete composite floor systems, and laminated veneer bamboo connections. Dr. Clouston is an author of more than 80 publications and teaches courses related to structural timber design, bio-based composites, and material mechanics/tectonics to architects, engineers, and building technologists. She is a registered professional engineer (EGBC) and serves as an Associate Editor of the ASCE Journal of Materials in Civil Engineering. Her notable contributions include leading the design and construction of a large student project, a Massive Timber Dome, and engaging in research that advances sustainable building systems and innovative timber construction methods.

Research topics

• Engineering
• Structural engineering
• Materials science
• Composite material
• Geometry
• Mathematics
• Geology
• Environmental science

Selected publications

• Index

  2026-01-16

  otherOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Mass Timber Systems for Lateral Loads

  2026-01-16

  other1st authorCorresponding

  A structure composed strictly of beams and columns may be adequate to carry gravity loads, but without bracing or other means, it will lack the ability to resist lateral loads. This chapter discusses different types of mass timber lateral systems and the fundamentals of their design. Lateral loads are those that act horizontally on buildings. High winds can generate substantial loads within a structure. Seismic forces are generated in buildings when the ground moves during an earthquake. Vertical ground motion also occurs during earthquakes, leading to vertical seismic forces in buildings. The effective transfer of lateral forces between lateral force-resisting systems elements is fundamentally reliant on well-designed connections. Diaphragm stiffness is influenced by the materials and composition of the diaphragm as well as its aspect ratio.

  PublisherDOI

• Case Study 3: Origine in Québec City, QC

  2026-01-16

  otherOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Structural Design Methodology for Mass Timber

  2026-01-16

  other1st authorCorresponding

  This chapter introduces the fundamental design code in the United States for all wood and wood products, including mass timber – the National Design Specification (NDS) for Wood Construction. It describes how designers make structural decisions using one of two possible design methodologies: Allowable stress design (ASD) or Load and Resistance Factor Design (LRFD). The NDS has a companion document called the NDS Supplement or simply the NDS-S. LRFD replaced ASD for steel and concrete because it offers a more rational approach to safety and reliability. The only way to truly know how strong something is, is to break it. As such, reference design values for all mass timber products are derived from experimental testing. Due to wood's many unique characteristics, there are a large number of adjustment factors for wood: some are applicable to certain products or applications while others are more universally applicable.

  PublisherDOI

• Design of Mass Timber Columns and Walls for Gravity Loads

  2026-01-16

  other1st authorCorresponding

  This chapter describes the behavior and design of columns and walls under pure axial compression forces, and discusses their response and design when subjected to combined compression and bending forces. Designers most often rely on tables or specialized software for compression member design. Bearing stress parallel to grain occurs when wood members bear on end grain, either with other wood members or with metal plates or strips. Bearing stresses are applied at an angle to the grain, such as at the support of a sloped roof panel. The chapter demonstrates some examples of axial compression design for glulam and cross-laminated timber using the allowable stress design procedure. Columns experience pure compression stresses while beams experience bending stresses, shear stresses, and bearing stresses.

  PublisherDOI

• Mass Timber in the Building Codes

  2026-01-16

  other1st authorCorresponding

  While mass timber buildings may appear as a recent phenomenon in architecture, it should be noted that solid and glue-laminated timber have been covered by various building codes for a long time. This chapter explores how building codes address mass timber structures and lays out what and how one can build with this material option. One building-code-sanctioned form of construction has become popular in recent years, mainly for light-frame residential buildings like apartments and hotels: podium construction. Once a feasible construction type has been determined, a set of detailed specifications need to be followed for the building design that cover minimum sizes, material options, and fire-resistance requirements. As is common practice, the IBC does not include all specifications in its text but rather references for various product and design standards that then become mandatory rules in jurisdictions where the IBC is implemented.

  PublisherDOI

• Wood as a Building Material

  2026-01-16

  other1st authorCorresponding

  The fact that wood is a natural building material provides it with many benefits. This chapter examines wood, its growth, and related properties: grain and cell structure, defects, the relationship between wood and water, dimensional stability, and various deterioration mechanisms (fungal decay, insects, weathering, and fire), as well as ways to address those. Trees can broadly be classified into two categories: softwoods and hardwoods. Many factors impact the geographic establishment of a particular tree species. From a biological perspective, tree growth starts with a process called photosynthesis. As a tree grows, it extends branches from its trunk outward and toward any available light. Wood's mechanical properties are evaluated in only two: parallel to the grain and perpendicular to the grain. Wood and water have an important relationship: Trees need water to live and prosper. An important concept that underlies the wood–water relationship is wood's hygroscopicity .

  PublisherDOI

• Mass Timber Building Systems and Their Layout

  2026-01-16

  other1st authorCorresponding

  This chapter serves as a concise guide to the most important aspects a designer must consider for mass timber buildings, along with associated best practices – a kind of “cheat sheet” for any building project. It provides a high-level overview of the many early design choices that mass timber designers face, outlining the available options along with their respective advantages and disadvantages. Owing to tree growth patterns and the resulting natural directionality of wood fiber in all wood-based products, wooden buildings generally exhibit certain basic material characteristics and typologies. Building-level layout concepts include choosing the structural system, panel layout, span capacities and optimization, primary/secondary beam hierarchy, interruptions in load flow and cantilevers, and long-span solutions. Detail-level concepts include column continuity, beam-column connections, panel connections, general connection considerations, and acoustics and vibration.

  PublisherDOI

• Mass Timber Fasteners

  2026-01-16

  other1st authorCorresponding

  This chapter covers many fastener types available to the timber designer today. It explains the structural behavior and design procedures of the fasteners. Screws are extremely versatile fasteners for mass timber and other wood structures. Nails are the simplest wood fasteners and are widely used in light-frame construction. Many heavy-load connections employ either bolts or drift pins as fasteners between the steel and the wood. In addition to mass-produced screws, nails, and bolts/dowels, there are many other types of connection hardware that are pre-engineered and can be used in standard and/or custom-designed situations. Of all the connection types, glued connections are by far the stiffest. To protect a fastener against corrosion and improve its durability, manufacturers are adding various treatments during the fastener's production process. These can include: coating, galvanizing and several combined coating types.

  PublisherDOI

• Design of Mass Timber Beams and Panels for Gravity Loads

  2026-01-16

  other1st authorCorresponding

  This chapter explores the design procedures for mass timber beams and panels in bending. It presents an overview of beam statics and strength of materials. The chapter then introduces design analyses addressing bending, shear, and deflection checks to ensure compliance with code-specified strength and deflection criteria. It provides several hand calculation examples and guidance on how to work with manufacturer design aids to streamline the design process. The chapter also provides a brief overview of beam behavior within the framework of material mechanics, assuming that the reader is already familiar with the principles of mechanics. Beam reactions occur at the supports as a result of applied loads. The chapter then provides some of the more common beam types and loading cases for mass timber. The deflection check ensures that the maximum beam deflection will be less than or equal to prescribed deflection limits.

  PublisherDOI

Recent grants

• Cross-laminated Timber Panels from Low-value Northeastern Woods

  NSF · $391k · 2015–2019

• Modeling the Design Limit States of Structural Composite Lumber

  NSF · $318k · 2009–2012

Frequent coauthors

• Sanjay R. Arwade

  University of Massachusetts Amherst

  22 shared

• Alexander C. Schreyer

  University of Massachusetts Amherst

  16 shared

• A. Bahmanzad

  ORCID

  8 shared

• Frank Lam

  University of British Columbia

  8 shared

• Larisa Brojan

  University of Ljubljana

  5 shared

• Russell Winans

  AIR Worldwide (United States)

  5 shared

• Alireza Amini

  University of Massachusetts Amherst

  4 shared

• Niloufar Khoshbakht

  4 shared

Education

• PhD Wood Mechanics

  University of British Columbia

  2001

• MASc Wood Mechanics

  University of British Columbia

  1996

• BASc Structural Engineering

  University of British Columbia

  1989