Goian – Cerveira Footbridge over the Miño River. Spain - Portugal

<p>The Goián - Cerveira footbridge over the Miño river, result of an international competition held in 2017, will connect the Espazo Fortaleza park in Goián-Tomiño, Spain, and the Castelinho park in Vila Nova de Cerveira, Portugal.</p><p>The proposed footbridge saves a main span of 265m, and is a suspended structure, with two towers located on the riverbanks, avoiding intermediate supports on the riverbed, and only one suspension cable. The towers are located not centered with the axis of the footbridge deck, that adopts a curved layout both in plan and in elevation. The curved layout in plan fits better to the footbridge arrival in both riverbanks, and improves its structural behavior. Indeed, the eccentric location of the suspension cable within the deck generates important horizontal transverse forces, that are supported by the curved deck by behaving as an arch. This configuration is also very convenient for supporting and controlling wind loads. It is a classic bridge type -suspended bridge- but with a singular configuration due to the curved layout of the deck and its arc-like behavior.</p><p>The result is a very subtle and slender structure, a “line over the Miño river”, that highly preserves the environmental values of the river and the landscape.</p>

An Experimental Study into the Behaviour of Tube and Fitting Scaffold Structures under Cyclic Side and Vertical Loads

The United Kingdom and European codes for the analysis and design of tubular scaffold structures assume that the scaffolds are subjected primarily to vertical loads and to horizontal loads at right-angles to the scaffold. The effects of dynamic loading caused by large winds tend to be ignored and the code analyses often only require static loading on the structures to be considered. To investigate side loads, a scaffold frame built according to the UK standard was made and inserted into a testing rig. Five different load combinations were made to determine the behaviour of the scaffold under different side loads, which were varied cyclically to simulate different wind loads, especially when vertical loads were also applied. The results showed that cyclical loads affected scaffold behaviour, especially when the bases of the scaffold standards were not tied to the base at the bottom of the test rig. Changes should be made to the UK and European codes BS EN 74.1, BS 5975 and BS EN 128 11-1 for the design of scaffold structures to increase safety.

Mitigating Safety Concerns of SRU Stack Using Advanced Analytical/Optical Technologies

Objective/Scope (25-75 word) In SRU, Tail gas exhaust stacks are provided with external cladding, preventing condensation beneath refractory surfaces. External cladding is made of individual Aluminium sheet panels, each 1.7mx1.5mx3mm thk, weighing 60Kg, attached by screws / rivets. Stack size is 6.5mdia × 90m height. Due to high wind, panel sometimes detaches from stack, falling down from 90m height, posing serious HSE threat to plant personal safety. This paper details an analytical design approach, supported with high resolution, remote controlled drone inspection technic to resolve one such issue. Methods, Procedures, Process (75-100 word) Initially, detached and dropped screws were observed, due to wind loads & vibration, which lead to falling of a clad panel from 80m height, fortunately, when no personal was below. Detailed finite element analysis of external cladding was performed, considering wind loads and thermal loads on panels with stack to panel joint configuration. Periodic inspection of the joints is vital to confirm reliability of the joints, which is not possible during operation with conventional inspection methods in an SRU exhaust stack. Hence, a latest technology, high-resolution, optical camera assisted, drone, controlled & monitored by remote computers were employed to assess the panel integrity. Results, Observations & Conclusions (100-200 words) Analysis Results Finite element analysis was performed for the stack cladding. As this analysis was non-conventional, there is no well-established industry acceptance criteria for the analysis results. Hence, an acceptance criteria was jointly developed with Contractor, which is fundamentally the minimum number of screws per panel, required to be intact, during the 2 year period, to confirm the panel integrity. Distance Drone inspection Manned inspection was not feasible in a running plant. Also, conventional aerial survey drones could not be engaged, as it was unsafe to fly the drone above live plant. Hence, an aerial drone with high-resolution optical camera, with overlapping method was employed. Advanced post processing software was used to analyse the images for best results. Conclusion To ensure clad panels integrity and 100% personal safety, Based on Finite element analysis, the original screws have been replaced with rivets with the following acceptance criteria. The integrity of the cladding remains intact even if 20% of the screws / rivets are lost whether it is consecutive or random. Above 20% there may be impact and further investigation is advised. Panels were monitored three times periodically in 2 year span to assess the fasteners intactness. The images from the optical camera, after software processing confirmed the fasteners integrity. Novel/Additive Information (25-75 words) 100% Plant and personal safety is ADNOC's principal objective. Occasionally, achieving this target require unorthodox analysis and acceptance criteria development. Most of all, the conventional monitoring technics, due to their limitations, pushes us to explore alternate technologies. The new high-resolution, optical camera assisted, drone technic can be engaged in a running plant and the images are processed using proprietary software to achieve best results of minute details.