NCST Technical Investigation of 

Hurricane Maria (Puerto Rico)

Performance of Critical Buildings Project

Project Leaders: Joseph Main and Marc Levitan

Objective: To characterize the performance of critical buildings in

Hurricane Maria by evaluating damage and loss of function for

representative hospitals, schools, and storm shelters with respect to

the hazards they experienced, including an evaluation of selection

criteria and design requirements for storm shelters.

NCST Advisory Committee Meeting 

– June 10

-11, 2021
Background and Motivation

2

Engineered buildings with good structural performance suffered significant 

damage to building envelopes, and penetration of rainwater resulted in 

extensive nonstructural damage and loss of function:

• roof covering and rooftop 

equipment damage from wind 

and windborne debris;

• window and door damage caused 

by wind and windborne debris;

• rainfall ponding on the roof due 

to excessive rainfall rates and 

debris blocking drains; and

• wind-driven rain penetration 

through undamaged cladding, 

such as windows and doors.

Loss of power and failure of backup generators also disrupted the function of 

some critical buildings, including hospitals, schools and storm shelters
Project Plan: Data Collection (1/2)

3

Initial Data Collection: Coordinate with Puerto Rico government agencies, federal 

partners, and others to identify and collect relevant existing data:

• characteristics and performance of hospitals, schools, and shelters

• shelter program information, including selection criteria and facilities used

Sample Selection: Select representative hospitals and schools/shelters for 

detailed evaluation, considering characteristics of buildings, hazards, other factors

Facility Evaluations: Collect information for selected critical facilities to document:

• Phase 1: initial document collection and review

• Phase 2: interviews, additional document collection (and field investigation)

Wind Tunnel Testing: Test scale models for a subset of the selected buildings

• building models will be extensively instrumented to measure wind loads

• effects of surrounding topography and buildings will be considered
Project Plan: Data Analysis (2/2)

4

• Evaluate the performance of selected critical buildings with consideration of:

− wind loads and other hazards encountered during Hurricane Maria

− damage to buildings and impacts on function of buildings and life safety of 

occupants, including operational challenges encountered 

− adequacy of existing codes, standards, and practices

• Evaluate shelter selection criteria, design criteria, and operational guidance for 

the larger population of shelters with consideration of:

− hazard levels encountered at shelter sites and damage to shelter buildings

− shelter population per site over time, including relocation of occupants

− adequacy of existing selection criteria, design criteria, and operations plans

• Develop findings and recommendations, as necessary, for specific 

improvements to building codes, standards, and practices based on the 

findings, including consideration of seismic hazards
Recent Progress: Initial Data Collection and 

Sample Selection

5

• Relational databases developed for 

linking various sources of information 

for hospitals and schools/shelters:

− hazard exposure at facility sites

− building characteristics

− reported damages

− shelter population over time

• Set of 10 “linking” hospitals selected 

to facilitate coordination across 

projects; five hospitals from this list 

selected for detailed evaluation

• Sampling strategy for schools/shelters 

is currently in development using 

information from database queries

Study Regions

Peak Gust Wind Speed with Topographic Effects

Landslide Density

Wind Speed (mph)
Recent Progress: Facility Evaluations

6

• Subcontract through Stantec established with University of Puerto Rico at 

Mayagüez to support facility evaluation work

• Facility evaluations in progress at 5 selected hospitals:

− NIST coordination with facility managers through emails and virtual meetings

− Phase 1 evaluations completed for 2 of the selected hospitals

− Phase 1 evaluations in progress for remaining 3 hospitals

• Initial observations from Phase 1 evaluations:

− Significant documentation obtained on building characteristics and damages

− Some linkages of damage to location are missing, and less information was 

obtained on function and operation; these items will be a focus in Phase 2

• Interview Guide for Phase 2 evaluations completed and translated to Spanish

• Project plans for evaluation of school facilities reviewed and approved by the 

Puerto Rico Department of Education
Recent Progress: Facility Evaluations

7

wind

rain

debris

flooding

landslides

rooftop equipment

roof cover

roof structure

walls

windows/doors

water/wastewater

power

transportation

communications

HAZARDS

HVAC

BUILDING COMPONENTS

INFRASTRUCTURE

protect contents

plumbing

generators

water tanks

foundation

electrical/lighting

elevators

communication

MECHANICAL & ELECTRICAL

BACKUP/STORAGE

protect occupants

FUNCTION

provide services

FACILITY

INTERIOR SPACE

FACILITY ACCESS

vehicle access

landing pad

floodwater intrusion

rainwater intrusion

DAMAGE

oxygen tanks

interior finishes, contents

designated safe areas

equipment (including medical)

debris penetration

ponding

hazard mitigation equipment

Scope of Data Collection
Recent Progress: Facility Evaluations

8

• Drone photography completed at two hospitals selected for wind tunnel testing:

− Hospital Bella Vista

− University Pediatric Hospital

• 3D point cloud models generated from drone images to support fabrication of 

wind tunnel models

Hospital Bella Vista Point Cloud Model University Pediatric Hospital Point Cloud Model
Recent Progress: Wind Tunnel Testing

9

The objectives for wind tunnel testing of Hospital Bella Vista are to evaluate:

• effects of topography on wind loads for a site with significant topographic speedup of 

winds (Topographic Speedup Factor of approximately 1.5 at hospital site)

• estimated wind loading history and peak loads sustained during Hurricane Maria

• adequacy of existing standard provisions (ASCE 7) to capture topographic effects

0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6

Topographic Speedup Factor

70

80

90

100

110

120

130

140

San Juan Region

Utuado Region

Caguas Region

Humacao Region

Other

Wind Speed, including Topographic Effects (mph)

Hospital Bella Vista Local elevation contours at hospital site

(Source: USGS)

Contour interval: 2 m

(1 mph = 0.447 m/s)
Recent Progress: Wind Tunnel Testing

10

• Design completed for Hospital Bella Vista building and area model (1:100 scale)

− Selected building (in red below) to be instrumented with pressure taps and base force balance

− Surrounding buildings and local topography to be included in area model

− Tests to be conducted both with and without the area model and surrounding buildings

• Measurements of approach flow velocity profiles at hospital site obtained from 

Mayagüez topographic model (1:3100 scale) using Particle Image Velocimetry (PIV)

• Approach flow profiles to be simulated using Flow Field Modulator

Mayagüez Topographic Model PIV Approach Flow Measurements Building and Area Model

Hospital Bella 

Vista site

Contour interval: 1 m
Next Steps

11

Sample Selection:

• Finalize selection of representative schools and storm shelters for detailed evaluation

Facility Evaluations:

• Complete Phase 1 evaluations of remaining 3 hospital facilities

• Initiate Phase 1 evaluations of selected schools/shelters

• Initiate Phase 2 evaluations of selected hospitals and schools/shelters

• Develop an integrated NIST/contractor database of information collected on hospitals and 

schools/shelters and begin data analysis

Wind Tunnel Testing:

• Complete fabrication of building and area model for Hospital Bella Vista and perform wind 

tunnel testing

• Complete design and fabrication of building and area model for University Pediatric Hospital 

and perform wind tunnel testing

• Combine measured data from wind tunnel testing of building models with time-dependent 

hurricane wind-field model to evaluate wind load histories for Hurricane Maria
NCST Technical Investigation of 

Hurricane Maria (Puerto Rico)

Performance of Critical Buildings Project

Project Leaders: Joseph Main and Marc Levitan

Project Team: Jazalyn Dukes, Cynthia Rivas, DongHun 

Yeo, Camila Young

Questions?

Please ‘raise your hand’ using the Blue Jeans 

Participant window and unmute your audio and 

video

NCST Advisory Committee Meeting 

– June 10

-11, 2021