Vincom Landmark Tower_Final Report_Cladding Wind Load Study

Rowan Williams Davies Irwin Inc. (RWDI) was retained by VINGROUP to study the wind loading on the proposed Vincom Landmark Tower in Ho Chi Minh City, Vietnam. The objective of this study was to determine the wind loads for design of the exterior envelope of the building.

INTRODUCTION

Rowan Williams Davies & Irwin Inc (RWDI) conducted a wind loading study for VINGROUP on the proposed Vincom Landmark Tower in Ho Chi Minh City, Vietnam The primary aim of this study was to assess the wind loads necessary for designing the building's exterior envelope.

The following table summarizes relevant information about the design team, results of the study and the governing parameters:

Structural Engineer ARUP Vietnam Limited of Ho Chi Minh City, Vietnam

Recommended Cladding Design Wind Loads

Figures 4a to 8 Figures 9a to 13 Range of Negative Pressures

-1.75 kPa to -4.75 kPa +1.25 kPa to +3.75 kPa

Corner Units Non-corner Units Non-glazed Horizontal Roof Areas

0.3 kPa Design Wind Pressure per Vietnamese Standard TCVN

Importance Factor on Wind Pressure 1.0

The wind tunnel test procedures met or exceeded the requirements set out in Section 6.6 of the ASCE 7-

This article outlines the test methodology for the current study, presenting the results and recommendations For further insights into the testing and analysis procedures, refer to Appendix A Detailed explanations of the methodologies and underlying theories can be found in RWDI’s Technical Reference Document on Wind Tunnel Studies for Buildings (RD2).

2000.1), which is available upon request.

WIND TUNNEL TESTS

Study Model and Surroundings

A 1:400 scale model of the proposed development was built based on the architectural drawings provided in Table 1b This model was equipped with pressure taps and underwent testing in a full-scale environment within a 460 m radius, utilizing RWDI’s 2.4 m × 2.0 m boundary layer wind tunnel facility located in Guelph, Ontario, for various test configurations.

Configuration 1 – Proposed development with existing and in-construction surroundings

Configuration 2 – Proposed development with existing, in-construction and future surroundings

Vincom Landmark Tower- Ho Chi Minh City, Vietnam Cladding Wind Load Study

To obtain further refinement at the top of the tower, a 1:100 scale model was constructed of the crown

(L78 and above) using the architectural drawings listed in Table 1b The large scale model was instrumented and tested in the same facility

This report consolidates cladding wind loads derived from two 1:400 scale model test configurations and one 1:100 scale model, creating a comprehensive set of design wind loads for cladding.

Figures 1a and 1b display photographs of the 1:400 scale model tested in the boundary layer wind tunnel for configurations 1 and 2, while Figure 1c features the 1:100 scale model in the same setting Additionally, Figure 2 provides an orientation plan indicating the location of the study site.

Upwind Profiles

The study simulated the impact of upwind terrain on the planetary boundary layer by incorporating suitable roughness elements on the wind tunnel floor and flow conditioning spires at the upwind section for various wind directions This approach aimed to accurately represent suburban areas characterized by low to mid-rise buildings Wind direction, defined as the origin of the wind flow, was measured in a clockwise manner from true north.

WIND CLIMATE

To accurately predict the full-scale wind pressures on the building according to different return periods, wind tunnel data were integrated with a statistical model reflecting the local wind climate This model utilized surface wind measurements from Tan Son Nhat International Airport, alongside a computer simulation of hurricanes developed by Applied Research.

Associates, Raleigh, NC using the Monte Carlo Technique Over 100,000 years of tropical storms were simulated to account for the variability of hurricane wind speed with direction

Figure 3 presents a comparative analysis of the strength and directionality of wind climates in Ho Chi Minh City, focusing on typhoons, thunderstorms, and extra-tropical winds The typhoon data is derived from computer simulations, while the thunderstorm wind climate is obtained by filtering local surface wind measurements to exclude non-thunderstorm days An hourly record is classified as part of a thunderstorm event if it occurs on a designated "thunder day."

Not all hourly thunderstorm records include a thunderstorm flag, and extratropical wind climates refer to wind measurements that do not pertain to thunderstorms or typhoons It is important to note that the provided plots are for illustrative purposes only and should not be utilized for predicting wind loads.

The upper two plots show the directionality of common winds on the left and extreme winds on the right

Hurricanes, classified as extreme weather events, are represented exclusively in the right plot, highlighting that the strongest winds originate from the west, with a notable secondary lobe from the south-southeast The lower plot illustrates the wind speeds associated with each data set in relation to their return periods.

The plot indicates that for shorter return periods, extratropical winds primarily influence common events, while for longer return periods, hurricanes are responsible for generating the highest wind speeds crucial for strength design.

For accurate wind loading predictions in strength design, the wind climate model was adjusted to align with a design wind speed corresponding to a 50-year return period This adjustment utilized a 3-second gust wind speed of 40.3 m/s at a height of 10 meters in open terrain, consistent with the reference wind pressure for the same return period.

99.6 daN/m 2 This pressure was derived based on the methodology provided in the Vietnamese Standard

TCVN 2737:1995; the nominal 95 daN/m² basic wind pressure (20-year return period) for the Ho Chi Minh

In Region II.A, initially classified as a "weak typhoon region," the wind load was reduced by 12 daN/m² This figure was then adjusted using a wind load reliability coefficient of 1.2, resulting in a design wind pressure of 99.6 daN/m² for a 50-year return period.

DETERMINING CLADDING WIND LOADS FROM WIND TUNNEL TEST RESULTS

When designing cladding elements, it is crucial to account for the net wind load affecting each element This report presents findings that encompass the wind loads impacting both the external surface—measured directly on the scale model during wind tunnel testing—and the internal surface, which is determined through analytical methods and data from the wind tunnel tests.

When assessing elements exposed solely to wind on their external surfaces, it is essential to incorporate an internal pressure allowance to the measured external pressure This adjustment is crucial for accurately determining the net pressure that will be used in the design process.

In high winds, air leakage significantly impacts internal pressures within buildings Key contributors to air leakage are small, uniformly distributed paths across the building's envelope, as well as larger openings These larger leaks often result from window breakage caused by debris during windstorms or from operable doors and windows left open.

In evaluating the risk of breakage or openings in the building's design, the internal pressure allowance values were established at +0.3 kPa and -0.6 kPa for corner units, while non-corner units, including non-glazed horizontal roof surfaces, were assigned a pressure allowance of ±0.3 kPa.

To determine the net peak negative pressure on a building's cladding, the negative exterior pressures were increased by the equivalent of the positive internal pressure Similarly, the net peak positive pressures were calculated by adding the exterior positive pressure to the magnitude of the negative internal pressure.

To assess the net pressure on elements like parapets, fins, and canopies that face wind on opposite surfaces, we measured the instantaneous pressure difference across these elements.

RECOMMENDED CLADDING DESIGN WIND LOADS

For optimal structural safety, it is advised to utilize the wind loads illustrated in Figures 4a through 13, which are based on a 50-year return period The zoning in these figures is defined by 0.5 kPa increments, indicating that the specified pressure represents the maximum pressure within each zone For instance, a zone marked as 2.25 kPa encompasses pressures from 1.76 kPa to 2.25 kPa.

The suggested wind loads are intended for designing cladding to withstand wind pressure, factoring in internal pressures However, designing cladding based on these wind loads may not fully protect against damage from wind-borne debris impact.

"Negative pressure" or suction is defined to act outward normal to the building's exterior surface and

The concept of "positive pressure" refers to forces acting inward, while the maximum recommended negative cladding wind load was recorded at -4.75 kPa, affecting the North, West, and East Elevations Most negative wind loads ranged from -2.25 kPa to -2.75 kPa In contrast, the highest recommended positive cladding wind load reached +3.75 kPa, specifically noted at the top of the spire.

West and East Elevations (Figures 10b and 12b) The majority of the positive wind loads were in the range of +1.75 kPa to +2.25 kPa.

APPLICABILITY OF RESULTS

The Proximity Model

The wind tunnel tests and analytical procedures used to determine cladding design wind loads are specific to the modeled surroundings, which reflect the development status at the time of testing, including anticipated nearby structures Future construction or demolition near the project site may alter these loads, so we recommend a minimum cladding design wind load of ±1.75 kPa, with a +1.25 kPa minimum for non-glazed horizontal roof areas It is important to note that these wind loads are based on the assumption that all horizontal roof surfaces are non-glazed; if this is not the case, RWDI should be consulted.

Study Model

This report details the findings based on the scale model of the proposed development, created using the architectural data outlined in Tables 1a and 1b Significant design modifications may lead to different results than those reported Consequently, any design changes should prompt a consultation with RWDI to assess the potential impact on wind loads.

TABLE 1A: DRAWING LIST FOR 1:400 SCALE MODEL

The drawings and information provided by Atkins were utilized to create the scale model of the proposed Vincom Landmark Tower in Vietnam Any design alterations that diverge from these drawings may impact the outcomes Consequently, it is advisable to consult RWDI for a review of any design changes to assess their potential effects on wind conditions.

File Name File Type Date Received

ATK-VINGROUP-COMBINED MODEL-20150515.3dm Rhino file 16/05/2015

TABLE 1B: DRAWING LIST FOR 1:100 SCALE MODEL

The drawings and information provided by Atkins were utilized to create the scale model of the proposed Vincom Landmark Tower in Vietnam Any design alterations that differ from these drawings may impact the outcomes, so it is advisable to consult RWDI to assess the potential effects on wind conditions if any changes are made.

File Name File Type Date Received

VINC-ATK-Z0-XX-M3-A-0000.rvt revit file 27/08/15

ATKINS 3D MODEL View03.jpg JPEG Bitmap 6/10/2015

151014 Feed back from Client/20151013_Comments.zip zip file 14/10/15

Wind Tunnel Study Model Figure No 1a Configuration 1

Date: Nov 26, 2015 Vincom Landmark Tower - Ho Chi Minh City, Vietnam Project #1501902

Wind Tunnel Study Model Figure No 1b Configuration 2

Date: Nov 26, 2015 Vincom Landmark Tower - Ho Chi Minh City, Vietnam Project #1501902

Wind Tunnel Study Model Figure No 1c 1:100 Scale Model

Date: March 11, 2016 Vincom Landmark Tower - Ho Chi Minh City, Vietnam Project #1501902

Directional Distribution of Local Wind Speeds Figure No 3

Date: November 26, 2015 Vincom Landmark Tower - Ho Chi Minh City, Vietnam Project #1501902

Note: Wind Speeds shown are 3-second Gust Wind Speeds (m/s) at 10 m height in Open Terrain

Extra-Tropical Typhoon Extra-Tropical + Typhoon TCVN 2737:1995 Design Wind Speed

SEE EAST ELEVATION SEE WEST ELEVATION

Vincom Landmark Tower - Ho Chi Minh City, Vietnam

The wind loads provided are unadjusted for load or safety factors and should be applied to the building's cladding system similarly to wind loads determined by standard building code analytical methods.

Recommended Wind Loads for Cladding Design (kPa)

(Negative External Pressure with Positive Internal Pressure Where Applicable)

50 - Year Reference Wind Pressure = 99.6 daN/m2, Importance factor = 1.0 1:750

Key Plan of Wall Surface (A)

The wind loads provided are unadjusted for load or safety factors and should be applied to the building's cladding system similarly to wind loads determined through standard building code analytical methods.

The wind loads provided are not inclusive of load or safety factors and should be applied to the building's cladding system similarly to how wind loads are determined through building code analytical methods.

The wind loads specified are without any load or safety factors and should be applied to the building's cladding system in a manner consistent with wind loads determined through building code analytical methods.

Key Plan of Wall Surface (B)

SEE WEST ELEVATION SEE EAST ELEVATION

The wind loads provided are not adjusted for load or safety factors and should be applied to the building's cladding system similarly to how wind loads are determined using building code analytical methods.

Key Plan of Wall Surface (C)

SEE WEST ELEVATION SEE EAST ELEVATION

The wind loads specified are presented without any load or safety factors and should be applied to the building's cladding system similarly to how wind loads are determined using building code analytical methods.

Key Plan of Wall Surface (C)

The wind loads provided are without load or safety factors and should be applied to the building's cladding system similarly to how wind loads are determined using building code analytical methods.

Key Plan of Wall Surface (D)

The wind loads specified are free of load or safety factors and should be applied to the building's cladding system similarly to how wind loads are determined using building code analytical methods.

True North Drawn by: JMS 8

The wind loads specified are without load or safety factors and should be applied to the building's cladding system similarly to wind loads determined by building code analytical methods.

Key Plan of Reflected Soffit Surfaces (F)

Key Plan of Roof Surfaces (E)

SEE EAST ELEVATION SEE WEST ELEVATION

The wind loads provided are unadjusted for load or safety factors and should be applied to the building's cladding system similarly to wind loads determined through building code analytical methods.

(Positive External Pressure with Negative Internal Pressure Where Applicable)

The wind loads provided are unadjusted for load or safety factors and should be applied to the building's cladding system in accordance with the analytical methods outlined in building codes.

The wind loads outlined are provided without any load or safety factors and should be applied to the building's cladding system similarly to how wind loads are determined using building code analytical methods.

Tiêu đề	Cladding Wind Load Study
Tác giả	Aleena Elizabeth Biju, Anusree Sushama, Kelvin Wong, Mphil, MHKIE, R.P.E., Mark Chatten, MICE, C.Eng., P.E.
Trường học	Rowan Williams Davies & Irwin Inc.
Thể loại	final report
Năm xuất bản	2016
Thành phố	Ho Chi Minh City

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Số trang	38
Dung lượng	3,65 MB