Bangladesh tragedy underlines how deficient building codes can fuel disasters

UN Office for Disaster Risk Reduction: The Head of the UN Office for Disaster Risk Reduction (UNISDR), Margareta Wahlström, today extended condolences to the families of those who have lost loved ones in the collapse of an eight-storey building in Dhaka, Bangladesh, and reiterated that Dhaka is also in a high risk earthquake zone.

In meetings last year in Dhaka, Ms. Wahlström urged Government ministers to update the National Building Code and strengthen its implementation to minimize casualties in view of the fact that over 40 million people in Bangladesh live in seismic zones.

She said today: "As we know from earthquakes, buildings kill more people than anything else. Bangladesh is a role model for many countries working to reduce deaths and losses from disasters and is a world leader in disaster risk reduction. The country has done excellent work in reducing mortality from cyclones and is poised to do an equally thorough job when it comes to updating the National Building Code and enforcing its implementation.

"The rapid pace of urbanization around the world means that sub-standard construction work is not just a problem in Bangladesh. We know that many governments are challenged by the task of ensuring adherence to land-use regulations and building codes. More people are living in seismic zones than ever before. We will have over six billion people living in urban areas by mid-century, up from around 3.5 billion people today. We can prevent many tragedies if we invest with care in new urban developments and public safety while raising awareness and commitment by citizens, business communities as well as the construction industry."

The Bangladesh capital, Dhaka, along with Barishal, Jamalpur and Sylhet have all joined UNISDR's Making Cities Resilient Campaign and are committed to implementing the campaign's Ten Essential actions to build resilience including better land use and adherence to strong building codes....

Hurricane Andrew disaster brought Florida-wide system of building codes

Mark Puente in the Tampa Bay Times: Hurricane Andrew's greatest impact on the building industry wasn't stronger nails or bigger trusses. It was a statewide building-code system.

Florida now regulates the inspection and enforcement of building codes and requires training and licensing for building officials and contractors. Continuing education is also required. Building officials and contractors can now be disciplined for not meeting requirements — something not done in 1992.

"This is the most fundamental change," said Douglas Buck, a director at the Florida Home Builders Association. "It's not just the building codes. It's whether you are complying with the codes."

On July 1, 2001, after fierce debate, the state adopted the stricter building codes with special provisions for new homes near the coast. The statewide system covers everything from roofing requirements to inspections to window protection.

It also required that many new coastal homes and buildings include hurricane shutters, impact-resistant glass or special internal construction designed to strengthen walls. The new code system unified hundreds of local building codes throughout the state...

Hurricane Andrew in 1992 scoured the Dadeland Mobile Home Park into nothingness. Photo from NOAA

Urban planning failures putting lives at risk

Katie Murray in AlertNet: Failures of urban planning are putting lives, infrastructure and businesses at risk as weather shocks – like the floods now surging through Bangkok – become more frequent as a result of climate change, urban planning and climate experts say.

But focusing on improving building codes, land use regulation, public health and sanitation, and disaster response measures could help reduce risks, said David Dodman, leader of the cities and climate team at the London-based International Institute for Environment and Development, which works on sustainable development issues.

“My concern is that the global framework for responding to climate change is basically entirely focused on (national) action. There is an important role for the nation-state, but there needs to be a greater focus on the role of localities, because they will play a major role in response,” said Dodman, one of the authors of a new briefing on “Urban adaptation planning: the use and limits of climate science.”

Failing to prepare for climate change effects is becoming increasingly riskier as severe weather becomes more frequent, and as the world’s urban population is expected to balloon from 3.3 billion to 5 billion over the next 20 years.

Dodman says cities need to make changes and adjustments in infrastructure and response systems to ensure that people have sufficient access to shelter, water, food, sanitation and information as climate change effects worsen. ...

View of the central square of Skopje, Republic of Macedonia. Results of the implementation of the first General urbanist plan in for Skopje by the new socialist authorities. Also, an example of modernist architecture and urban design in a neoclassical city

Building codes may underestimate risks due to multiple hazards

The National Institute of Standards and Technology (US Department of Commerce): As large parts of the nation recover from nature's one-two punch—an earthquake followed by Hurricane Irene—building researchers from the National Institute of Standards and Technology (NIST) warn that a double whammy of seismic and wind hazards can increase the risk of structural damage to as much as twice the level implied in building codes.

This is because current codes consider natural hazards individually, explains NIST's Dat Duthinh, a research structural engineer. So, if earthquakes rank as the top threat in a particular area, local codes require buildings to withstand a specified seismic load. In contrast, if hurricanes or tornadoes are the chief hazard, homes and buildings must be designed to resist loads up to an established maximum wind speed.

In a timely article published in the Journal of Structural Engineering, Duthinh, NIST Fellow Emil Simiu and Chiara Crosti (now at the University of Rome) challenge this compartmentalized approach. They show that in areas prone to both seismic and wind hazards, such as South Carolina, the risk that design limits will be exceeded can be as much as twice the risk in regions where only one hazard occurs, even accounting for the fact that these multiple hazards almost never occur simultaneously. As a consequence, buildings designed to meet code requirements in these double-jeopardy locations "do not necessarily achieve the level of safety implied," the researchers write.

Simiu explains by analogy: a motorcycle racer who takes on a second job as a high-wire performer. "By adding this new occupation, the racer increases his risk of injury, even though the timing and nature of the injuries sustained in a motorcycle accident or in a high-wire mishap may differ," he says. "Understandably, an insurer would raise the premium on a personal injury policy to account for the higher level of risk."...

Wind zone map shows how the frequency and strength of extreme windstorms vary across the United States. Wind speeds in Zone IV (red), where the risk of extreme windstorms is greatest, can be as high as 250 miles per hour. Credit: Federal Emergency Management Agency

Increase in tornado, hurricane damage brings call for more stringent building standards

Science Daily: Researchers from a team funded by the National Science Foundation have examined some of last spring's massive tornado damage and conclude in a new report that more intensive engineering design and more rigorous, localized construction and inspection standards are needed to reduce property damage and loss of life. As one of the nation's most destructive tornado seasons in history begins to wane, and hurricane season approaches its peak, experts are working to determine if old, tried-and-true approaches to residential and small building construction are still adequate, or if it's time to revisit these issues.

"Modern building codes are not what we would call inadequate, but they are kind of a bare minimum," said Rakesh Gupta, a professor of wood engineering and mechanics at Oregon State University, and one of the members of the NSF team that traveled to such sites as Tuscaloosa, Ala., and Joplin, Mo. -- where a massive EF5 tornado in May killed more than 150 people and caused damage approaching $3 billion.

"Beyond that, in the actual construction process, buildings are often not built precisely to codes, due to inadequate construction work or code enforcement," he said. "We can do better. The damage didn't have to be as bad as it was. We can design and build structures more rigorously that could withstand wind forces up to 140-150 miles per hour, which would help them better resist both tornadoes and hurricanes." ...Among the findings of the new report:

• It's not possible to economically design wood-frame structures that could resist damage from the highest winds in extreme tornado events, such as EF4 or EF5, but irreparable damage from lesser winds could and should be reduced.
• Tornadoes and hurricanes apply different types of forces to buildings, and what will adequately protect from one type of storm event isn't identical to the other. Implementing hurricane-region construction practices in a tornado-prone region is a good start, but not an end solution.
• Vertical uplift, one of the special risks from tornadoes, is often not planned for in traditional construction approaches.
• Interior closets and bathrooms can provide some protection at lower wind speeds, but more consideration should be given to construction of "safe rooms" that can save lives in major events.

A tornado rips through Springfield, Massachusetts, on June 1, 2011, shot by Matt Putzel, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Tornadoes raise questions about building practices, code enforcement

University of Oregon: There is no practical, economic way to build structures that could stand up to the savagery of EF5 tornadoes like those that ripped through the South in late April, experts say, but damage from lesser storms could be reduced by better building practices and better enforcement of existing codes.

Researchers with a rapid assessment team supported by the National Science Foundation say that much of the damage could be linked to inadequate connections between building members, especially trusses, roof rafters and walls. And even though modern codes are generally adequate, they said, such codes are not always followed or enforced.

The result last month, one day of which has been called the fifth deadliest day of tornadoes in the nation’s history, was 305 tornadoes, three of which were the maximum “EF5” category, that killed at least 326 people and may have caused more than $5 billion in damage.

“We often found inadequate or no connections at critical locations in structures, such as attaching the trusses or rafters to the supporting walls, or sill plate to the foundation,” said Rakesh Gupta. He is a professor of wood science and engineering in the College of Forestry at Oregon State University, an expert in wind loading and structural resistance, and was a member of the NSF research team.

“Time and again we’ve seen that such connections are often inadequate under extreme loading conditions,” Gupta said. “For instance, trusses that were just toe-nailed to the walls often failed in the high winds, the roof blew off and that allowed the rest of the building to collapse. And in some cases there were no anchor bolts between the bottom plate and foundation, allowing the whole building to shift off the foundation.”

The final report from the assessment team is not yet complete, but early observations pointed not just to building codes, but enforcement of those codes, Gupta said. “In one town in Alabama, I was told there is no inspection of homes by the city building inspector,” he said. “Property taxes are very low, inspection is often inadequate, and sometimes that can result in inadequate construction quality and enforcement.”

In many cases with the largest tornadoes, the researchers concluded, no existing codes or even quality construction practices made a difference. “In an EF5 tornado, we observed that even new buildings built with the latest codes were totally destroyed,” Gupta said. “One complex had used hurricane clips on trusses, the code-required nailing of roof and wall sheathing, and anchor bolts every four feet. It was destroyed right down to the concrete slab.”…

A picture of the Tushka, Oklahoma tornado, an EF3 which struck the town on April 14, 2011 during the Mid-April 2011 tornado outbreak. Shot by Gabe Garfield and Marc Austin of the National Weather Service

Adapting to global warming the key to Vietnam's sustainable development

VietNam Net Bridge: Urban development must develop in a manner that takes climate change into account, including more green building, experts said at an international conference held in HCM City yesterday, Feb 27. Speaking at the conference, Olavo Rasquinho, secretary of the Typhoon Committee, an intergovernmental body based in Macau, said ineffective land-use planning, waste management and infrastructure construction would make cities more vulnerable to climate change.

If governments do not take climate-change adaptation seriously, flooding in particular would increase in frequency and intensity, causing damage to property, livelihoods, human health and economies. Rasquinho pointed to the example of downtown Beijing, where more rain is falling compared to suburban areas because of the number of tall buildings affecting the formation of clouds.

"Urban flooding is not an isolated issue and it should be integrated with urban system or planning," he said, suggesting that cities should engage in international cooperation to increase the managerial capacity of urban planners.

Melissa Susan Merryweather, coordinator of Viet Nam Green Building Council, told the conference attendees that architectural models should be chosen according to the kind of climate zone. "Western architectural prototypes are suitable for northern climates, but are less appropriate in a hot tropical climate," she said. She urged builders and investors to follow Viet Nam's new LOTUS system, somewhat similar to the LEED standard in the US, which awards points to green construction…

Expert rejects shift of Australia's cyclone zone

Bill Hoffman in the Sunshine Coast Daily (Australia): The planned shift of the east coast cyclone zone south to cover the Sunshine Coast and Caboolture was a politically motivated exercise that had generated considerable cynicism from the engineering community. That is the opinion of Dr George Walker who wrote the post-Cyclone Tracy engineering report that reset Australian building codes.

He said current standards, where new Coast buildings were required to be able to withstand a category three cyclone, were reasonable The Australian Building Codes Board is considering a draft report that recommends the Cyclone Region C boundary, which starts near Cairns and ends south of Bundaberg, be changed to take in the Coast and Caboolture.

Builders fear that would add up to $15,000 to the cost of a new home although this estimate has been questioned by some engineering experts who say the actual component costs would be significantly less. Dr Walker, of Mapleton, who has studied tropical cyclones and their effects on building for the past 40 years, said the zone change appeared to be a purely political exercise by a government wanting to be seen to be doing something about global warming.

No climate-change sceptic – he is a peer science reviewer for the International Panel on Climate Change – Dr Walker remains highly sceptical of the cost-benefit of the zone shift which he says stops conveniently short of the state’s capital where it would have the greatest impact on disaster mitigation. He said too much emphasis was being applied to upper range impacts of climate change….

Torn shade sails in Townsville after Cyclone Yasi, shot by Rob and Stephanie Levy, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license