NEWBuildS Tall Wood Building Design Project – Seismic & Gravity

Load Analysis and Design

Zhiyong ChenUniversity of New Brunswick

www.NEWBuildSCanada.ca

1. Introduction

1.1 Customer Demands & Challenges on Structures

Taller Buildings Structural systems: Ductile Connection systems: High strength & Ductile

Larger Open Space Floor systems: Long span & Vibration

We are trying to address these issues !!!

[Yes]

1.2 Flow Diagram

Checking on Structural & Fire Issues using FEA

Suitable Structural Assembles & Connections

Structural SystemMaterial,

Structural Assembles& Connections

Site & Loads(Dead, Live, Wind, Snow and Seismic)

Structural Sketch& Report

[No]

1~3 Iteration

s

2. Structural Design

2.1 Concept Design

Structural System Post-beam system Shear wall system Shear wall + core system

Shear Wall Construction Platform framing: Easy to be built storey by storey Balloon framing: Reduce the storey joints

Possible storey number

+

-

2.1 Concept Design

Stiffness, Strength & Ductility

CoreShear Wall

Steel Beam

Vertical Joints(Dowel Type)

Shear Connector

Hold-Down

(1)

(2)

(3)

(3)

2.2 Lateral Load Resisting System

Shear Connector

LLRS

The typical storey

HSK System(Wood-Steel-Composite)

Hold-Down

2.3 Gravity Load Resisting System

GLRS

The typical storey

Beams are divided by column / wall

2.3 Gravity Load Resisting System

GLRS

The typical storeyFloor

2.3 Gravity Load Resisting System

GLRS

The typical storeyRoof

2.4 Design Assemblies and Connections

Material Type CompanyRoof CLT panel SLT9 STRUCTURALAM

FloorGlulam-concrete composite deck

HBV-Vario Floor

(125mm Concrete + 175x532mm GL beam @ 800mm)

TICOMTEC

GL Beam Glulam D.L.F. 24f-E (215x532mm)Steel Beam Steel G50 (S5x10)

GL Column GlulamD.L.F. 24f-E (730x418=2-365x418,

365x418mm)Core & Wall LSL 2.1E LSL (3-19x2.44x0.089m ) TIMBERSTRANDHold-Down Steel and Glue HSK system TICOMTEC

Shear Connector

Steel and Glue HSK system TICOMTEC

Vertical Joint

Steel Dowel type connector

2.5 Sketch List

GENERAL G-01: PROJECT DECRIPTION AND SKETCH LIST

STRUCTURAL S-01: STRUCTURAL SYSTEM DESCRIPTION S-02: TYPICAL FRAMING PLAN S-03: TYPICAL BUILDING SECTIONS S-04: TYPICAL DETAILS S-05: TYPICAL DETAILS S-06: CONSTRUCTION SEQUENCE DIAGRAMS

3. Structural Analysis

3.1 Massive-Timber-Panel Moment Frame Steel Beam

Vertical Joints

Shear Connector

Hold-Down

(1)

(2)

(3)

(3)

MTPMF

3.1.1 Influence of Hold-Down

3.1.1 Influence of Hold-Down

Deformation Hysteresis loops

The ductility of the hold-down affects the system ductility.

3.1.2 Influence of Steel Beam

3.1.2 Influence of Steel Beam

Deformation Load-deformation curve

Steel beam increases the system stiffness and ductility.

3.1.3 Influence of Vertical Connections

3.1.3 Influence of Vertical Joint

Vertical joint affects the performance of the system. Deformation Load-deformation curve

(1) Stiffness of Vertical Joint

(2) For a denser fastening case, the system derives a higher stiffness in the rigid case.

(1) The ratio system stiffness increases with increasing the stiffness of the vertical joint.

(2) Strength of Vertical Joint

(2) The first turning point of the curves from the infinite-connections-strength to zero-connection-strength cases increases with increasing the

connection strength.

(1) The curves of the two extreme cases form the boundaries of the other intermediate strength cases.

(3) Ductility of Vertical Joint - Static

The first yield point increases with increasing ductility ratio of the connection.

(4) Ductility of Vertical Joint - Cyclic

The system ductility and energy dissipation ability are improved by the ductile connections.

3.2 FEA Model of Tall Wood Building

Geometrical Model and Elements LSL core, shear wall & diaphragm Shell element – S4R Steel & glulam beams, columns Beam element – B31

Material Models Timber – Elastic Steel – Ideal Elastic-Plastic

Strain

Stress

Strain

Stress

3.2 FEA Model of Tall Wood Building

Connection Models Vertical joint & shear connector – Ideal Elastic-Plastic with ductility

Hold-down connection – Ideal Elastic-Plastic with ductility under tension & without movement under compression

Deformation

Force

Deformation

Force

3.2 FEA Model of Tall Wood Building

Connection Models Steel beam & GL column – Rigid connections GL beam to beam, column, wall & diaphragm – Hinge connections

Contact Models Steel beam to Wall – Tie Panel to panel – Frictionless (in tangential direction) – Hard contact (in tangential direction) Strain

Stress

3.2 FEA Model of Tall Wood Building

Numerical Simulation Problem• 3-Dimentional• Non-linear

Problem Size• Number of elements is 90,834

• Number of nodes is 154,592

• Total number of variables 585,762

(Degrees of freedom plus any Lagrange

multiplier variables)

It is a huge & complex computational task with convergent problems

3.3 Frequency Analysis

Sub-Space Method

In Y (N-S) direction In Z (rotation) direction In X (E-W) direction

3.3 Frequency Analysis

Influence of joint stiffness

T1 T2 T3

Rigid 1.04 (Torsional) 0.88 (N-S) 0.64 (E-W)Semi-Rigid 1.66 (N-S) 1.46 (Torsional) 0.94 (E-W)NBCC Shear wall: 1.04; Moment Frame: 1.90

The fundamental period of this building with semi-rigid joints in the East-West direction is close to that estimated by NBCC.

Semi-rigid FEA should be used, else the periods of the building would be under-estimated.

3.3 Frequency Analysis

0.94S

1.66S

1.46S

(1) Wind would control the structural design in the North-South direction, while seismic would control it in the East-West direction.

(2) Some external walls at axis 1 & 7 should be considered to address the torsional issue and the stiffness in N-S direction.

(L=37.3+30.6=67.3m)

(L=60.5m)

3.4 Gravity Loading Analysis

3.4 Gravity Loading Analysis

In X (E-W) direction In Y (N-S) direction

The differential shortening is not significant.

Risk method

3.5 Pushover Analysis

In X (E-W) direction In Y (N-S) direction

Seismic response of the high-rise wood building is crucial in the ultimate limit state.

Investigation method: Nonlinear time history analysis 22 “Far-Field” earthquake records will be scaled at the

corresponding fundamental period of the building model to match the spectral acceleration, Sa, of the Vancouver design spectrum.

3.6 Seismic Analysis

3.6 Seismic Analysis

Thank you!

Yingxian Wood Pagoda (67.31m)

Tall Wood Building (66m)