Shotcrete has been used widely for rehabilitation and retrofit of concrete structures. More and more large infrastructures, in particular, in the hydro power industry, is using shotcrete for major rehabilitation and retrofit. Recently, the US Army Corps of Engineers has been engaged in structural modifications to reinforced concrete draft tube exits from the turbines in the Ice Harbor Lock and Dam located on the Snake River, Washington. This presentation details the structural modification to the draft tube which was successfully completed using wet-mix shotcrete.
The general sentiment around construction and modern technology is that the industry has been slow to embrace it. While this is true of the past, the current and future construction industry is all about modern technology. Not only does technology help to make the industry safer (something that has been a struggle for a very long time), but it is helping contractors to take back control of their budgets, to make smarter choices about project planning and equipment and is, consequently, pushing the green-construction trend forward. The purpose of this presentation is to provide a summary on the current technologies being used in the construction industry with a focus on concrete and to dig even further as to how these can be applied to repair projects. It will provide case studies on how using technology to bring ambient and concrete temperature, relative humidity and strength (among other) data online can help contractors be more efficient.
Technology is not limited to innovative materials or equipment on a jobsite. Digital technology is changing how teams operate and is dramatically increasing efficiency and effectiveness. Cloud-based project management software allows key stakeholders to consolidate project data on to one mobile platform for easy collaboration. The entire project team, from general contractors, specialty contractors, owners, architects, engineers, conservators, and others can exchange data and documents with the tap of a screen. Communication between the field and the office is streamlined where everyone has access to real-time project details. This helps avoid duplicate entry errors and rework because teams built from an outdated drawing. In addition to drawings and details, project management software brings contracts, submittals, RFIs, billings, safety reporting, meeting minutes, photos, and financial reporting into one platform.
The prestressed beams in the Hampton Roads Bridge Tunnel Approach Spans were fabricated in about 1960 (west bound lane) and 1970 (east bound lane). The spans are 50-ft and 75-ft, respectively. The brackish water environment caused corrosion and failure of the bottom strands and deterioration and spalling of the cover concrete in many beams. A project in 2018 strengthened 30 of the more deteriorated beams as an alternative to posting or replacing the bridges. Carbon fiber composite wrap (CFCW) and external post-tensioning (PT) were used to strengthen the beams. Prior to construction, a PT mockup was done with one 50-ft (flexible filler) and one 75-ft (grout) beam to demonstrate that the contractor had the materials, equipment and staff to successfully do the external PT. This presentation describes the project’s mockups and construction and the anticipated increase in strength to be obtained from application of the CFCW and external PT.
This update includes fall protection requirements for low slope roofs, façade access, and ladders as well as a timeline for compliance. This seminar not only addresses the recent 2017 updates to 29 CFR Part 1910 General Industry, but is an overview of all fall protection standards found in both Part 1910 for General Industry and Part 1926 Construction. The components of a Comprehensive Managed Fall Protection Program are also presented as well as specific requirements for the fall protection options available. Because many in the industry either do not understand the standards, are unaware of the available OSHA interpretations, or prefer not to spend money training their employees, misinformation is being spread. This seminar provides the truth about the required implementation of the updated fall protection standards and the standards that remain in place.
In new construction, cracks can appear for variety of reasons: curing, temperature deviation, pressure from adjacent conditions, or settlement. This presentation will outline various types of cracking, how to plan to avoid them, and how to address them after concrete has been placed.
The iconic construction hard hat, a symbol of pride for the construction worker, has changed very little in 50 years. Developments in the understanding of the causes and prevention of debilitating and often fatal head injuries is leading to a revolutionary change in the way we protect our people from head injuries on the jobsite. The classic hard hat is about to change forever. This presentation will focus on new technology available today to minimize the effects of falls and impacts to the head of the worker. We will also focus on new technologies, already in development, that can further provide protection from head injuries. Industry requirements (OSHA, ANSI) will be reviewed, and the application of worldwide standards (EN) will be discussed and applied to new helmet development and implementation.
The Avalon Mall parking facility is a four level above grade structure, consisting of three suspended parking levels (approximately 7,750sq.m. each) and one on-grade parking level connected to the existing mall with a new pedestrian bridge. RJC was the structural engineer of record. During construction of the parking structure extensive cracking of the suspended parking garage slabs was noted at two of the 24 pours. RJC undertook a visual assessment of the parking slabs in question to determine the extent of the noted cracking and determined over 750lin.m. of cracks ranging in size from 0.5mm to 6.5mm in width. Following the visual assessment destructive testing of the concrete was undertaken to determine its in-situ properties as well as to understand the full extent of the cracking.
Dealing with water is always a challenge when constructing a new structure. Whether it is water infiltration that was expected, or water manages to circumvent pre-planned waterproofing methods, it can wreak havoc on the building and interfere with construction schedules. The term “belt and suspenders” is often used in waterproofing and there is a good reason for it. Water chooses the path of least resistance, and many times that path is not discovered until it is too late. There are many methods of water control that can be implemented before, during and after a structure is completed. This presentation will focus on water control methods for new construction that can be implemented during or after the construction process.