METHODOLOGY FOR HURRICANE DAMAGE ESTIMATION TO GLAZING SYSTEM TOWARDS PROBABILISTIC LOSS ASSESSMENT

ABSTRACT

Hurricanes can cause extensive damage to the building and the envelope systems of commercial buildings as documented over the past several decades in the United States. This study focuses on improving the performance of commercial buildings and minimizes losses caused by hurricane hazards. For this reason, the study intends to develop a better understanding of the performance of glass panels as building envelope that helps in performance design methodology.

The objective of this study is to make contributions to the Performance-Based Engineering (PBE) design based on fragility information developed from actual hurricane reports. The fragility curves for the failure of glass panels of building envelope caused by wind-borne debris (WBD) give the loss for the exterior of the building, which leads to immediate damage, while the fragility information of wind-driven rain (WDR) through the broken glass panels provides the loss the interior of the building.

The approach that will be followed or developed as appropriate can be used in the more practical application of Performance-Based Hurricane Engineering that can result in mitigating building envelope losses due to hurricane effects.

TABLE OF CONTENTS

List of Figures ………………………………………………………………………………………………………….. vii

List of Tables …………………………………………………………………………………………………………… ix

Acknowledgements …………………………………………………………………………………………………… x

Chapter 1 Introduction ………………………………………………………………………………………………. 1

1.1 Background information ……………………………………………………………………………….. 1

1.2 Objective …………………………………………………………………………………………………….. 2

Chapter 2 Literature Review ………………………………………………………………………………………. 4

2.1 Introduction …………………………………………………………………………………………………. 4

2.2 Hurricane damage report ……………………………………………………………………………….. 4

Hurricane Katrina ……………………………………………………………………………………….. 5

Hurricane Ike ……………………………………………………………………………………………… 8

2.3 Impact of shingle missiles on glazing ……………………………………………………………… 12

Experimental Laboratory Test Configuration …………………………………………………. 13

Test materials …………………………………………………………………………………………….. 15

Failure status determination …………………………………………………………………………. 16

Impact procedure ………………………………………………………………………………………… 16

Experiment results ………………………………………………………………………………………. 17

2.4 Summary …………………………………………………………………………………………………….. 20

Chapter 3 Research approach ……………………………………………………………………………………… 22

3.1 Damage caused by WBD ………………………………………………………………………………. 23

3.2 Damage caused by WDR ………………………………………………………………………………. 23

3.3 Performance-based hurricane engineering design and cost estimate of repair ………. 24

Chapter 4 Fragility function development methodology, PBD approach and WDR study ….. 25

4.1 Review of fragility development method …………………………………………………………. 25

4.2 Development of fragility functions …………………………………………………………………. 26

4.3 Wind-driven rain research ……………………………………………………………………………… 29

WDR definitions and parameters ………………………………………………………………….. 30

Rain Admittance Factors ……………………………………………………………………………… 31

WDR intrusion …………………………………………………………………………………………… 33

4.4 Performance-based engineering (PBE) ……………………………………………………………. 34

4.5 PBE methodology ………………………………………………………………………………………… 35

4.6 Summary …………………………………………………………………………………………………….. 36

Chapter 5 Fragility information for WBD based on lab tests ………………………………………….. 38

5.1 Fragility functions and curves development …………………………………………………….. 38

5.2 Limitations of lab experiment ………………………………………………………………………… 40

5.3 Summary …………………………………………………………………………………………………….. 41

Chapter 6 Fragility information for WBD based on actual hurricane damage …………………… 43

6.1 Case study of WBD using hurricane report ……………………………………………………… 43

6.2 Fragility information of WBD using hurricane report ……………………………………….. 45

Case 1 ……………………………………………………………………………………………………….. 45

Case 2 ……………………………………………………………………………………………………….. 46

Case 3 ……………………………………………………………………………………………………….. 47

Case 5 ……………………………………………………………………………………………………….. 49

Results based on hurricane reports ………………………………………………………………… 50

6.3 Fragility development of WBD using hurricane report ……………………………………… 51

Damage state ……………………………………………………………………………………………… 51

Assumptions ………………………………………………………………………………………………. 51

Development ……………………………………………………………………………………………… 52

6.4 Summary …………………………………………………………………………………………………….. 55

Chapter 7 Fragility information for WDR based on actual hurricane damage …………………… 57

7.1 Fragility information of WDR using hurricane report ……………………………………….. 57

Case 1 ……………………………………………………………………………………………………….. 58

Case 2 ……………………………………………………………………………………………………….. 58

Case 3 ……………………………………………………………………………………………………….. 59

Case 5 ……………………………………………………………………………………………………….. 60

Results based on hurricane reports ………………………………………………………………… 61

7.2 Fragility development of WDR using hurricane report ……………………………………… 62

Development of breakage information …………………………………………………………… 62

Development of water intrusion information ………………………………………………….. 64

7.3 Summary …………………………………………………………………………………………………….. 66Chapter 8 Repair Cost ……………………………………………………………………………………………….. 67

8.1 Repair cost of the exterior of the building………………………………………………………… 67

8.2 Repair cost of the interior of the building ………………………………………………………… 69

8.3 Case study using fragility information …………………………………………………………….. 70

Chapter 9 Summary and Conclusions ………………………………………………………………………….. 72

References ……………………………………………………………………………………………………………….. 77

Chapter 1 

Introduction

1.1 Background information

Hurricanes have always caused extensive property damage, mainly to the envelope systems of residential and commercial buildings in coastal cities with better documentation of such damages in the past several decades. While damage to residential buildings has usually been more extensive due to the type of construction (i.e., wood-frame structure with siding and shingles as the exterior skin of the envelope) and the much larger number of residential buildings compared to commercial buildings, this study is focused mainly on commercial buildings. Acceptable structural and nonstructural systems performance would mean injury to occupants should be avoided, but it is also desirable to minimize damage with economic consequences. In particular, building envelope components such as glazing system can be very expensive to replace (FEMA 757_ch5). According to recent reports (FEMA 757, FEMA 549), for commercial buildings located in center business areas (downtowns), most of the damage under hurricane conditions is due to non-structural building components damage, such as damage to glazing systems and claddings. Damage types can be divided into two parts, which are immediate damage and long-term damage. For immediate damage, all losses occur instantly due to direct wind pressure, flying debris impact, or rain water intrusion. Physical damages to building envelope including broken glass in windows or curtain walls and building cladding damage may be followed by water intrusion through broken glass, which can cause further damage to building interior. Long-term damage including water absorption by building envelope components will likely cause more serious problems after some time if not repaired properly.

In order to improve the building envelope system performance of commercial buildings and minimize losses due to hurricanes, it is necessary to have a better understanding of fragility information for building envelope systems under hurricane conditions. Since the overall repair cost estimation is to be considered, not only repair cost due to the immediate damage but also the cost due to potential long-term effects should be accounted for.

1.2 Objective

The main objective of this study is to develop a better understanding of the performance of glazing systems as a building envelope system type under real hurricane conditions that will result in prediction and minimization of losses caused by hurricane hazard. By generating fragility data for envelope systems made up of different materials from FEMA report and other resources, it is possible to develop the framework for consideration of building envelope damage that can be used for performance-based hurricane design. In order to measure the damage or loss of the building in hurricane condition, two types of damage, including material breakage and water intrusion in building, need to be determined.

This study presents a review of damage reports due to hurricanes that have occurred in the past few decades in the United States to get a better understanding of the damage first in Chapter 2. Experimental studies related to wind-borne debris (WBD) impact on glass panels are used for fragility curves development, with the testing procedures and data resulting from tests described in Chapter 2. More cases based on FEMA reports related to WBD are described in Chapter 2; these cases are also used for WDR study. Chapter 3 presents the research approach in this study. Chapter 4 presents a review of the methodology of fragility development used in this study;  the previous research on WDR and PBE is also discussed in the chapter. The fragility information based on lab tests is developed in Chapter 5, where the limitation of lab test data is also explained. Chapter 6 and Chapter 7 illustrate the generation of data from actual hurricane reports and the development of fragility information for WBD and WDR, respectively. Chapter 8 discusses the repair cost development using fragility information for WBD and WDR, and ends with a case study.

METHODOLOGY FOR HURRICANE DAMAGE ESTIMATION TO GLAZING SYSTEM TOWARDS PROBABILISTIC LOSS ASSESSMENT