Extreme weather events are becoming more frequent, powerful and erratic.

These trends are expected to continue and science assessment reports have concluded man-made climate change is likely to be responsible. Among the many adaptation challenges is the need to ensure buildings are resilient to dramatic shifts in weather patterns. With the addition of Texas-based Haynes Whaley Associates in 2013, Cardno has enhanced its ability to safeguard large structures from a range of environmental threats. These can include earthquakes, fire and blasts, as well as climate-related activity such as hurricanes, tornadoes and flooding.

In addition to providing structural engineering services across the United States and the world for many years, many projects have been based in and around Texas and the Gulf of Mexico. It is a region susceptible to hurricanes and tornadoes and the wild winds and floodwaters that accompany them.

"Many of our projects are designed to withstand wind gusts of 110 miles per hour, which produce 50 per cent higher loads than winds for buildings not subject to hurricanes," says Wally Ford, Executive Vice President with Cardno Haynes Whaley. "It really requires creative solutions in order to maintain the design intent, while keeping the costs as low as possible for our clients."

For low-rise buildings, the structural costs incurred are primarily due to horizontal framing, roofing and cladding, while the primary costs for high-rise buildings are the lateral stability system and overall overturning resistance of the structure. About 80 per cent of the work Cardno does in this area is on buildings designed to withstand tropical weather events, with engineers using a number of tools and methods to secure the best results.

One example is wind tunnel studies where a scaled model is constructed with pressure gauges that can test extreme wind conditions from every direction, as well as taking into account other structures that are within 2,000 feet.

"These tests determine the wind shears and overturning moments we use to design the overall structure," says Ford. "They also measure maximum wind pressures across the building's surface. This allows window frame designs to be optimised based on their location on the building.

"We can also work out how often the wind will be uncomfortable for pedestrians near the building, and what level of wind storm will make the occupants uncomfortable due to the building moving in the wind."

The ability to use fully computerised, three-dimensional models has been highly beneficial for Cardno's structural engineers.

"We moved on from hand drawings and calculations of capacity moments, to two-dimensional AutoCAD drawings and simplified computer studies, and now full 3D documentation and analysis," says Ford. "The evolution to more modern methods has allowed us to design more complex structures in less time, which is great for clients."

Cardno is committed to sustainability through the use of recycled or reusable materials, and incorporates structural elements into designs to allow such features as water collection tanks and energy harvesting heating systems. It is also well known for its collaborative approach and ability to develop creative solutions to both accomplish design goals and respond to environmental challenges that may exist.

"We work closely with the owner and design team to determine the best structural solution for each project, whether commercial, public or institutional," says Ford. "We are skilled at retrofitting and modifying existing facilities, undertaking damage assessments after storms and suggesting repairs when required."

Ultimately, there is one driving force for all of Cardno's structural engineering work: safety.

"The first commitment of civil engineers is to protect the public and that underpins everything we do," Ford points out. "Strict fire and seismic guidelines must be met and, as weather events change, we will adapt accordingly so our clients will remain confident their buildings are safe and secure."

Cardno is playing a key role in the reconstruction of a hospital in Galveston, Texas, after it was ravaged by
Hurricane Ike in 2008. Cardno structural engineers faced substantial challenges to ensure the 12-storey Jennie Sealy Replacement Hospital project is more resilient in the face of natural disasters.

The facility was designed using advanced wind tunnel testing including forces in excess of code-prescribed loads. Administration offices are situated on level two of the building, which includes an emergency operations centre capable of
managing a major event for up to seven days.

Underground column transfers and strap beams are included to assist with stabilising the foundation and building construction. Located on the University of Texas Medical Branch (UTMB) campus, the hospital will operate as a "living classroom" and a platform for the translation of basic biomedical research into better care.

IT WILL INCORPORATE:

  • 256 patient rooms
  • 54 dedicated intensive care rooms
  • 20 surgical suites
  • 28-bed day surgery centre

Cardno is providing engineering services for a critical biosecurity and public health facility in Kansas. Housed in an efficient and secure building, the National Bio and Agro Defense Facility (NBAF) has been constructed to study foreign animal, emerging and zoonotic diseases that threaten the United States.

Due to its location on the Kansas plains, it has been designed to withstand a category EF5 tornado with wind speeds up to 230mph, as well as vehicular and debris impact.

The NBAF is also designed for progressive collapse, allowing the building to stand if some of the structural members become
compromised or destroyed. The building will provide the United States with critical capabilities to develop vaccines and other countermeasures, as well as train veterinarians to prepare and respond to these diseases.

The progressive nature of the facility is further advanced with sustainable water management strategies, green roofs, onsite renewable energy and automated building system controls, such as daylighting controls and occupancy sensors.

Contact Cardno
Wally Ford, Executive Vice President, Cardno Haynes Whaley
Phone: +1 713 868 1591
Wally.Ford@cardno.com

For project enquiries:
Mark Thompson, Executive Vice President, Cardno Haynes Whaley
Phone: +1 713 868 1591
Mark.Thompson@cardno.com

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