When it was first conceived, the Golden Gate Bridge raised concerns over its ability to withstand the location's extreme weather conditions. For civil engineers, weather is just one element that must be considered when ensuring the safety of a structure's architectural components. Here, Sam Carigliano, CEO and Co-Founder of cloud-based structural engineering software provider SkyCiv, explains how structural software can be used for safe construction.
Located at the intersection of two active tectonic plates, San Francisco is prone to earthquakes. When creating the iconic Golden Gate bridge, the designers therefore had to consider factors like this to ensure the finished bridge would be safe and structurally sound.
The original design submitted by Joseph Strauss pictured a hybrid suspension span that was supported at each end by cantilever trusses. Much like today's design process, other engineers joined the project to consult on the safety and viability of the project.
Structural engineers have a responsibility to protect those that are constructing the building from risks to their health and safety. In this instance, the consulting engineers persuaded Strauss to change the design of the bridge to the all-suspension design, which stands to this day.
Structural engineers are, above all else, risk managers. Despite the use of computers and sophisticated machinery, the construction industry is still largely people-dependent. This is because many of the processes and checks, particularly at the design check level (DCL), are dependent on various individuals reviewing the final drawings, calculations and specifications.
In the U.S., the DCL outlines four steps that should be taken to meet the minimal requirements for checking any errors in the design. By following the DCL, structural engineers can eliminate problems that occur because of design errors.
Research has shown that between 25 and 35 percent of construction failures in the U.S. and Europe occur because of engineers inappropriately applying design codes to the construction of their project, or due to failure to translate design assumptions to the construction of the works.
The practice of structural engineering has changed considerably over the last two decades, developing into a complex specialism that involves close collaboration with professionals across various other construction sub-disciplines. This includes site appraisals, environmental studies and also geotechnical and geological investigations, which examine the loading and foundation of the design.
In fact, the work of structural engineers is greatly impacted by the project's geography. This is because building regulations can vary for each country, including the design codes and health and safety regulations.
These regulations can also be limited to a particular state, so structural engineers should be particularly aware of the specific local requirements for their projects.
Across the U.S., there was a period where nearly every city had its own building code for structural engineers to comply with. Due to the increasing complexity and cost of developing these regulations, nearly every jurisdiction across the country has now adopted a model code. Chicago is the only municipality that continues to use a building code developed on its own.
In countries like New Zealand, structural engineers generally come under scrutiny if there is a construction accident. This is not the case in every country and so engineers need to determine what the obligations and responsibilities are, before conducting any work for a project.
There are numerous other practices that civil and structural engineers can follow that are endorsed by local authorities Design for safety (DfS), which is also referred to as prevention through design, safe design and construction design management, considers health and safety issues during the design phase of a project.
By identifying these potential problems in the early stages of designing, engineers can effectively eliminate or intervene and control these hazards. This often creates a safer worksite for those constructing the final structure.
The DfS knowledge greatly relies on engineers familiarizing themselves with the knowledge, but it is practiced across the globe in countries like Australia and the United Kingdom.
With such a wide range of regulatory considerations, many structural engineers understandably feel overwhelmed at the outset of a new international project. Fortunately, managing and abiding by specific regulations in different countries is becoming easier to achieve with software advancements.
Now, engineers can conduct numerous tests on their structures by using specialist software, which checks their calculations and sequences to ensure the design is safe by relevant geographic standards.
Structural engineers are responsible for keeping themselves up-to-date with any changes in regulations and, as much of the work is on a contractual basis, being familiar with all local regulations can be a challenge.
With SkyCiv's cloud-based structural engineering suite, updates are rolled out as quickly as possible after a regulation is revised without any additional update or maintenance fees. This allows civil and structural engineers to continue designing structures that safely comply with up-to-date standards.
As well as carrying out a series of checks by various individuals, engineers can use software to test out the codes simultaneously. This helps engineers ensure their design performs safely to the required weight and resistance, all at a minimal cost. These calculations can then also be quickly and efficiently amended if seen unfit for purpose.
For locations like San Francisco, structural engineering is about ensuring a structure can withstand environmental factors. Not complying with building codes has contributed to high losses during earthquakes, as demonstrated by investigations of the Northridge earthquake in California. Engineers must therefore input additional safety measures to protect their structure.
In fact, while constructing the Golden Gate bridge, builders implemented shock absorbers that are specially designed vibration dampers made of a lead core covered by rubber. They are located at both ends of the bridge to absorb any energy coming from high winds or seismic activity that could cause the bridge to collapse.
Health and safety should be at the forefront of a project, but with the numerous regulations and advisory boards centralized around the construction industry it's easy to see why many areas may be overlooked. By using structural software in addition to the standardized checks and processes already in place, engineers can ensure structural safety in most scenarios.