INNOVATION May-June 2018

Project Highlights •

+ CLARIFIER DOMES FOR A TREATMENT PLANT Chemposite Inc., of Delta, BC, conceived and designed a series of dome assemblies for a wastewater treatment plant for the City of Moose Jaw. The purpose of the domes is to prevent the plant clarifiers from freezing in the winter and having algae growth in the warmer months. The domes are ventilated and operate with a nominal negative air pressure, with heated makeup air during the winter. A total of 224 fibreglass parts were made for the project using advanced fabrication methods. The 30-metre span required an innovative design of the individual components, configured to fit inside standard shipping containers. The segments consist of an insulated sandwich with inner and outer skins bonded to each other. Polyurethane foam was injected between the faces for insulation. The dome assemblies were completed on site in January 2018. Owner: City of Moose Jaw. Project consultant: Stantec Regina. Dome concept and design: Marvin Hlynka, P.Eng., Chemposite Inc. AUTOMATED LEVELLING SYSTEM FOR A CRANE BARGE The Dynamic Beast , commissioned in September 2017, has a 900-ton lift capacity, making it the largest crane barge stationed on the west coast of North America. Morrow Engineering Ltd. was retained to design and implement a dynamic levelling system, which actively corrects the barge listing under heavy-lift operation. The control system receives angle feedback from strategically placed servo inclinometers and calculates a precise two-dimensional response angle. In auto mode, this information levels the barge by engaging up to four pumps and hydraulic valves to move water within a closed system of trim tanks. An extended web of sensors monitors the barge, constantly searching for abnormalities; a comprehensive alarm and process interlock system assures safer operation. The crane can operate efficiently at high speeds in its zero- degree chart with confidence, dramatically reducing lift time. Client: Dynamic Heavy Lift. Morrow Engineering Ltd.: Evan Sherman, P.Eng., Kris Montpetit, EIT, Rushat Agarwal, EIT FAILURE ANALYSIS OF A LARGE CLEVIS HOOK One of two forged-steel clevis hooks supporting a gantry crane fractured, resulting in the collapse of the gantry crane. The failed clevis hook was recovered and examined in order to determine the cause of its failure. Examination of the large fracture surface was performed with a high-resolution three-dimensional optical microscope instead of a conventional scanning electron microscope (SEM). Fractographic interpretation of micron-scale details revealed by the 3-D optical microscope confirmed that the clevis hook failed due to an overload. Compared to the SEM, the high-resolution 3-D optical microscope enabled rapid determination of the cause of failure and avoided cutting the large fracture into many smaller pieces. Project owner: MEA Forensic Engineers & Scientists. Mark Bailey, P.Eng., Dennis Turriff, P.Eng. (PEO), Chris Tranquada, EIT (PEO)

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