Scope creep is a constant plague on some if not every project. As typical projects proceed, the client (Owner, Architect, or Contractor) requests alternatives to the original design, more features, attendance at additional meetings, presentations to stakeholders, and other efforts beyond those defined in the Scope of Work contained in the contract. …
Leslie E. Robertson Associates was an Award Winner for its Lotte World Tower project in the 2016 NCSEA Annual Excellence in Structural Engineering Awards Program in the Category – New Buildings over $100M.
At 1,820 feet (555 meters) tall, the 123-story Lotte World Tower stands as the first supertall building in South Korea, more than 1.8 times taller than the previous tallest building (located in the nearby city of Incheon). The building topped out in December 2015 and the tower’s mast, dubbed the “Lantern,” was complete in March 2016. …
The start of a career as a young engineer is a continual information overload. The facts to remember and considerations to take when making design decisions are overwhelming. Keeping up with tight deadlines leaves little extra time to spend understanding the process and building confidence in making decisions. Brand new engineers lack the basis to distinguish which design checks are necessary, which are extraneous, and how to be efficient in calculations and designs. …
A few years ago, shortly after I had moved into our founding partner Roger’s office, I sat down to start my day. As I was looking at my busy calendar (meetings, reviews, financials, etc.), I noticed a small piece of paper taped to the wall where Roger might have seen it every day as he sat down at his computer. On it was this simple message, “All professionals owe a debt of time and talent to the enhancement of their profession.” For a moment, I stopped focusing on the company’s bottom line and began to recall the many ways in which he embraced this message and encouraged the rest of us to do the same. …
Post-installed expansion anchors are used to attach fixtures to concrete and masonry. Expansion anchor types include torque-controlled anchors, which must be torqued to expand wedges, and displacement-controlled anchors, which require impact forces on a sleeve or plug to expand wedges. Expansion anchors that rely on torque to expand wedges are referred to as torque-controlled expansion anchors. This article discusses the importance of torque on the installation and performance of torque-controlled expansion anchors installed into concrete. …
Improving Performance of Concrete Structures
Corrosion of steel reinforced concrete affects everyone, leading to expensive repairs and intensive maintenance programs. Budgeting of repairs and maintenance programs becomes difficult when structures do not meet their intended life cycle requirements. Corrosion of reinforcing steel in concrete structures leads to concrete failure, impacting the public with delays and detours. …
According to recent industry reports, 6,500 people have been injured from collapsing balconies and decks in the United States since 2003. Complicating matters for existing homes, the North American Deck and Rail Association (NADRA) estimates there are 40 million decks in America that are more than 20 years old. This means these decks were installed prior to today’s building codes. …
A bridge structure exposed to salt can expect corrosion of the embedded steel during its service life. Cathodic Protection (CP) has proven itself as the only permanent repair of existing corroded steel reinforced concrete. Therefore, CP must not be considered separately, but as a part of a complete rehabilitation program. (1993 Strategic Highways Research Program (SHRP) Report S-337) …
Taking the Bridge-Building Prize
For centuries, bridges and other structures were big, bulky, visually disruptive hulks. Stone, iron, and concrete made them symbols of strength and stability. Solid construction helped people feel more confident about crossing or entering them. …
Introduction to Designing with ASCE 7-16
The title of ASCE 7-16 is Minimum Design Loads and Associated Criteria for Buildings and Other Structures. This article is the first in a series intended as an introduction to the seismic design of the “other structures,” commonly known as nonbuilding structures. …