Fuß‐ und Radwegbrücke aus Carbonbeton in Albstadt‐Ebingen

Pedestrian bridge made from carbon‐concrete in Albstadt‐Ebingen – First entirely carbon‐reinforced concrete bridge worldwide The bridge erected in Albstadt‐Ebingen in October 2015 is realized without any steel reinforcement or pre‐tensioning, making it the world's first entirely carbon‐reinforced concrete bicycle and pedestrian‐bridge. The trough section with material thicknesses of 70 mm (trough walls) and 90 mm (slab) respectively has been fabricated as monolithic pre‐cast element. With a span length of 15 m and a width of 3 m, the bridge‐deck requires no further coating and has a total weight of just 14 tons (approximately 310 kg/m2); this is about 50 % of comparable conventional reinforced concrete bridge‐decks. Besides material and weight savings, an exceptionally long service life with minimal maintenance can be expected, as the steel corrosion that is typical in reinforced concrete structures can be entirely avoided. Since the use of carbon‐reinforced concrete (carbon concrete) is not yet approved in Germany, the client had to obtain approval based on individual cases (ZiE).     

Das Schiffshebewerk am Drei‐Schluchten‐Staudamm,China – Bau des größten Fahrstuhls der Welt

The ship lift at the Three‐Gorges‐Dam in China – Construction of the world's largest elevator With a total height of 169 m, a maximal lifting height of 113 m and moved masses of approx. 33 000 t, the ship lift at the Three‐Gorges‐Dam in China will be the largest of its kind worldwide. The entire structure is nearing completion. Operational testing started in 2015. Located parallel to the existing fully operating five stage ship lock at the 2,3 km long barrage, the ship‐lift consists of four RC towers. A steely, water filled ship chamber with 132 m length, 23 m width and 10,5 m height will lift ships with a max. water displacement of 3 000 t. The construction gains its flexibility from an innovative combination of structural and mechanical parts. Since 2008 the ship lift structure was erected by climbing formwork. Due to the tolerances demanded by the embedded parts of the mechanical drive system, a special procedure of 1st and 2nd stage concrete and grouting had to be developed. The article describes the structural aspects of the project with focus on the execution.     

Zerstörungsfreier elektrochemischer Chloridentzug an der Donaubrücke Pfaffenstein: Langzeiterfahrungen über eine bauwerksschonende und verkehrserhaltende Technologie

Non‐Destructive Electrochemical Chloride Extraction on the Danube Bridge Pfaffenstein: Long‐Term Experiences about a Structure‐ and Traffic‐keeping Technology Between 2003 and 2007 in total 200 m² of corrosion active hollow box girder floor slabs were rehabilitated by a non‐destructive, electrochemical chloride extraction (ECE) within the Danube bridge Pfaffenstein that is situated in Regensburg along the highway A93. These concrete areas were chloride contaminated by a leaking drainage system from the carriageway above – up to 4% by cement mass. Hence, the reinforcement was corrosion active, but did not show considerable loss of cross‐section or concrete deterioration. After completing the ECE, where more than 28 kg of chloride could be removed, multiple potential surveys have been made about a time span of up to three years. These measurements have shown that chloride induced corrosion activity could be eliminated safely, also with some residual chloride. Both highway and a heavy traffic bearing main street, which crosses under the bridge, haven't been affected by the repair. The principle of ECE, its side effects and the experiences collected by the author since 2001 shall be discussed here.     

Eine Finite‐Elemente‐Lösung auf der Basis eines erweiterten eindimensionalen Querschnittselementes für die freie Torsion dünnwandiger prismatischer Stäbe

A finite element solution on the basis of an extended one‐dimensional cross‐section‐element for the Saint‐Venant torsion of thin‐walled prismatic beams. It is presented a finite element solution on basis of an extended one‐dimensional cross‐section‐element to the calculation of the warping function, the torsional properties and the shear stresses, dependent on it, for thin‐walled prismatic beams under Saint‐Venant torsion. The formulated finite two‐node‐element with six element degrees of freedom can capture through inclusion of the torsion around the element axis the linear term of the variance of warping function perpendicular to the element axis. Only the shear stresses of the ring shear flows in the closed section parts unchangeable over the wall thickness can be calculated with the simple two‐node‐element with two element degrees of freedom. The extended two‐node‐element supplies in addition also the shear stresses of the cut open cross‐section linearly changeable over the wall thickness.     

Geotechnical considerations in an unlined high pressure tunnel at Lower Kihansi in Tanzania

The Lower Kihansi unlined high-pressure tunnel is the first of its kind to be constructed in Tanzania. The pressure tunnel consists of a 500 m vertical shaft and a 2.195 km inclined headrace tunnel. The cross sectional area of the shaft is 25 m² and that of the headrace tunnel is 30–37.5 m². The headrace tunnel slopes 1:7 towards the powerhouse cavern. The pressure tunnel acts as waterway towards the underground hydroelectric power generation plants with a maximum generating capacity of 180 MW. The Kihansi River has been deviated through the shaft and headrace tunnel from an elevation of 1,146–300 m above sea level. The maximum water pressure created by this deviation is 8.5 MPa.The decision not to steel line the pressure tunnel was reached after the excavation and documentation of the underground rock mass. The hydraulic jacking and hydro-fracturing tests confirmed the rock to have a minimum acceptable confining stress of 9.6 MPa, capable of withstanding the expected water pressure in the tunnel. The permeability of the rock mass is relatively low and any poor zones were sealed by grouting.The discontinuities had a favourable orientation with respect to the tunnel axis such that rock bolts and steel fibre reinforced shotcrete could be used to provide the necessary support. No failures occurred and the decision not to line the Kihansi high-pressure tunnel has proved both technically acceptable and economical.     

Tragverhalten von geschichteten Deckenelementen aus Normal‐ und Porenleichtbeton

Load bearing behaviour of layered ceiling elements made of regular and porous lightweight concrete Lightweight and efficiently bearing steel reinforced elements may be achieved through the application of regular and porous concrete in a three‐layer cross‐section. While exterior layers of higher strength carry bending moments, a lightweight core layer material holds up to shear stresses. In order to quantify the potential of this construction method, the bearing behaviour of 18 layered ceiling elements with six different geometries was investigated. The goals were both to identify different failure modes, as well as evaluate the suitability of commonly used calculation procedures. The following paper shows that an optimal usage of cross‐sections of ceiling elements can already achieved by using concrete with strengths between 5 MN/m² and 20 MN/m². The efficiently bearing elements are characterized by the fact, that both the concrete, the reinforcing steel and the layer's interface are highly stressed both under pressure and tension. The tested specimens showed both a tensile bending and interface failure with a partly very high utilization of the flexural compressive zone.     

京杭运河扬州段航道整治工程建设与养护分析

京杭运河扬州段航道整治工程自2006年7月至2011年5月完成。工程交工验收以来,整体运行情况较好。目前,扬州段已勾画出一条优质、生态、和谐的航道,达到航道安全通畅、运能大幅提升、航道建设与城市发展相协调的整治效果。     

Ultrafine,fine, and black carbon particle concentrations in California child‐care facilities

Although many U.S. children spend time in child care, little information exists on exposures to airborne particulate matter (PM) in this environment, even though PM may be associated with asthma and other respiratory illness, which is a key concern for young children. To address this data gap, we measured ultrafine particles (UFP), PM_2.5, PM₁₀, and black carbon in 40 California child‐care facilities and examined associations with potential determinants. We also tested a low‐cost optical particle measuring device (Dylos monitor). Median (interquartile range) concentrations for indoor UFP, gravimetric PM_2.5, real‐time PM_2.5, gravimetric PM₁₀, and black carbon over the course of a child‐care day were 14 000 (11 000‐29 000) particles/cm³, 15 (9.6‐21) μg/m³, 15 (11‐23) μg/m³, 48 (33‐73) μg/m³, and 0.43 (0.25‐0.65) ng/m³, respectively. Indoor black carbon concentrations were inversely associated with air exchange rate (Spearman's rho = ?.36) and positively associated with the sum of all Gaussian‐adjusted traffic volume within a one‐kilometer radius (Spearman's rho = .45) (P‐values <.05). Finally, the Dylos may be a valid low‐cost alternative to monitor PM levels indoors in future studies. Overall, results indicate the need for additional studies examining particle levels, potential health risks, and mitigation strategies in child‐care facilities.     

Submicrometer particle removal indoors by a novel electrostatic precipitator with high clean air delivery rate,low ozone emissions,and carbon fiber ionizer

A novel positive‐polarity electrostatic precipitator (ESP) was developed using an ionization stage (0.4 × 0.4 × 0.14 m³) with 16 carbon fiber ionizers in each channel and a collection stage (0.4 × 0.4 × 0.21 m³) with parallel metallic plates. The single‐pass collection efficiency and clean air delivery rate (CADR) were measured by standard tests using KCl particles in 0.25–0.35 μm. Performance was determined using the Deutsch equation and established diffusion and field charging theories and also compared with the commercialized HEPA filter‐type air cleaner. Experimental results showed that the single‐pass collection efficiency of the ESP ranged from 50 to 95% and decreased with the flow rate (10–20 m³/min), but increased with the voltage applied to the ionizers (6 to 8 kV) and collection plates (?5 to ?7 kV). The ESP with 18 m³/min achieved a CADR of 12.1 m³/min with a voltage of 8 kV applied to the ionization stage and with a voltage of ?6 kV applied to the collection stage. The concentration of ozone in the test chamber (30.4 m³), a maximum value of 5.4 ppb over 12 h of continuous operation, was much lower than the current indoor regulation (50 ppb).     

Design & practice on engineering projects of specially deep & big excavation in Shanghai

This paper briefly describes two engineering projects of specially deep and big excavation,Jin Mao Mansion and Heng Long Square with depth of 19.65m and 18.20m, and area of about 20 000m² and 25 000m², respectively. Based on the comparison of design, construction and monitoring between these two projects,a design idea on specially deep and big excavation is presented.     

Aquatics Centre,London 2012 Olympic and Paralympics Games

The Aquatics Centre is a centrepiece of the London 2012 Olympic and Paralympic Games. Already now before the opening of the Games it is regarded as an iconic legacy building. The building comprises a 50 m competition pool and 25 m dive pool under the wave‐form roof of the main pool hall. A 50 m training pool is situated beneath the Olympic Park entrance plaza structure which is built integrally with the rest of the building. The engineering strategy has been developed around two basic configurations; the Games mode and Legacy Mode. In the Games mode the facility has a maximum gross spectator capacity of 17 500 for use for the London 2012 Games as well as housing facilities for the running of these events. In that mode temporary stands to the east and west of the competition and diving pools will seat approx. 15 000 spectators. In the legacy mode the building temporary seating will be dismantled and the building will be a permanent pool facility for the local community as well as national and international swimming events beyond the Games. Each pool tank is provided with a combination of floating floors and movable sub‐division boom bulkheads to allow multiple legacy and community use. Schwimm‐Arena der Olympischen und der Paralympischen Spiele London 2012 Die Schwimm‐Arena ist eines der Hauptgebäude der Olympischen wie auch der Paralympischen Spiele in London 2012. Schon vor Beginn der Spiele wurde es zu einer baulichen Ikone. Unter einem wellenförmigen Dach befinden sich ein 50‐m‐Schwimmbecken sowie ein 25‐m‐Becken mit Sprungtürmen. Das 50‐m‐Aufwärmbecken liegt unter einem der Eingänge zum Olympia Park, der so genannten Plaza. Die ingenieurtechnischen Planungen erfolgten gemäß den unterschiedlichen Anforderungen der “Games Mode” und der “Legacy Mode” nach den Spielen. Während der Spiele bestehen Tribünenplätze für 17 500 Zuschauer sowie alle damit verbundenen sonstigen räumlichen Anforderungen. Die westlich und östlich der Becken gelegenen temporären Tribünen nehmen 15 000 Zuschauer auf. Für die “Legacy Mode” werden diese wieder abgebaut und die Schwimmhalle wird dann von der breiten Öffentlichkeit und für nationale wie internationale Schwimmwettbewerben genutzt. Alle Schwimmbecken verfügen über höhenverstellbare Böden und Unterteilungen.     

Building Budapest's new reservoir

Nearing completion on Gellert Hill overlooking the Danube at Budapest is an enclosed pianoshaped water reservoir of 80 000 m³ capacity. The complexities of this waterproof, stressed concrete structure, which entailed placing 2 000 m² of base slab in 41 hours and erecting walls in situ in 20 m sections 350 mm thick and 10 m high, presented several technical challenges.

They are discussed here by the department head of the Civil Engineering Design Enterprise, Mélyépterv.     

Großversuch WILD‐Brücke – versuchsgestützte Bemessung einer UHPC‐Bogenbrücke

Full‐Scale Experiment Bridge WILD – Design of an UHPC Arch Bridge based on Experiments The outstanding durability of UHPC makes this material predestined for the construction of bridges. In Austria UHPC is introduced into the practice of road bridges through the realisation of the bridge WILD. The cross section of the arch, which spans 70 m, is just 6 cm thick and doesn't contain any passive reinforcement. The design is based on international recommendations on the one hand and on specific experiments on the other hand. This paper deals with the evaluation of two full‐scale laboratory tests. The setup is configured for getting a broad field of results as it is necessary for approval tests. In this way, all critical design states, which are also determined by calculation, are investigated experimentally. Furthermore, the experiments cover secondary effects, which don't have any verification through practical experience but can clearly be seen in FE‐results. The test results are carefully interpreted and explained by the use of simple mechanical models. The final examination of the results is figured out by means of comparison between calculation and experiment.     

浅埋大跨公路隧道施工技术

某隧道最大开挖跨度达16.4 m,高跨比仅有0.57,洞口段埋深较浅,属典型的大跨公路隧道。根据大跨扁平隧道的受力和变形特点,在施工过程中采用小导管超前支护加固围岩,CD工法分块开挖并及时进行支护,同时进行拱顶沉降监测,保证了施工安全。     

A practical study of white‐clawed crayfish (Austropotamobius pallipes) mitigation during in‐channel construction works,North‐East England

The article provides a unique opportunity to study a large white‐clawed crayfish mitigation exercise on the River Wansbeck, Northumberland in North East England. The translation was necessary to allow the construction of a dam on the river to reduce flood risk to the town of Morpeth. The study provides an assessment of the methodology used for the capture and translocation activities, and provides an insight into the speed of colonisation and population establishment in a 300‐m diversion channel and the structure of translocated populations. Over 3500 + white‐clawed crayfish were caught when the natural channel was dewatered, with 5400 animals removed the following year when the diversion channel was closed. Average density based on the number of white‐clawed crayfish caught was estimated as in excess of 5 per 1 m². The study demonstrates the importance of the River Wansbeck for white‐clawed crayfish.     

Computational study of flow characteristics of acid mine drainage on the structure of oxidation pond

A computational flow analysis using the concept of the inflow age was conducted to evaluate the flow characteristics and retention time depending on the shape and number of inlets and outlets in an oxidation pond. The oxidation pond was rectangular in shape with a width‐to‐length ratio of 3, a depth of 3 m, an area of 500 m², and square‐shaped inlet and outlet. The flow rate of the mine drainage was set to 5 L/s. The computational flow analysis showed that the homogeneity and inflow exchange efficiency were the highest when the width‐to‐height ratio of the inlet and outlet was 0.5, while they were the lowest when it was 1.0. The number of inlets in the oxidation pond had a significant effect on the flow characteristics in the pond, whereas the number of outlets had no significant effect. The homogeneity and inflow exchange efficiency appeared to be the highest when the number of inlets was two.     

Experimental thawing of permafrost soils in bases of reconstructed main building of the Chita-I Thermoelectric Power Plant

Conclusions 1. Compaction of thawed soils takes place directly during the thawing process or in the first 10–35 days after it. The thawed soils do not require subsequent compaction and, as regards the load-carrying properties, they are comparable to similar rocks in a naturally thawed state.2. The specific electric energy consumption for thawing 1 m³ of permafrost soils in bases is 25.2 kWh, and it is a fundamental characteristic in the design of industrial thawing of soil bases for determining the spacing between the heaters their capacity, and the thawing period.3. In test thawing, the number of ground mark vertical lines and the number of marks in each vertical line should be determined from the degree of heterogeneity of the frozen soils as regards the collapsibility in plan and section. For permafrost soil conditions similar to those of the construction site of the Chita-I plant, the optimal solution is to lay one vertical line per 100–120 m² of thawing area, and to use in each vertical line not less than one mark per 5 m of section of thawed permafrost soils."Atomteploelektroproekt" Institute, Novosibirsk. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 9–10, September–October, 1986.     

Urban development and particulate air pollution in Coimbatore city,India

Haphazard urbanization and unprecedented vehicular growth that exacerbate air quality are prevalent features in India. Coimbatore, an important industrial city ranking 15th in terms of principal urban agglomerations of India, was classified as a moderately polluted area in National Ambient Air Quality Monitoring survey in 1997. The current study (March 1999–February 2001) was undertaken to assess suspended particulate matter (SPM) in urban and suburban Coimbatore. It was found that in the Coimbatore atmosphere SPM with a diameter of less than 10 µm (respirable fraction, RSPM or PM₁₀) and those with a diameter above 10 µm, the non‐respirable (NRSPM) fraction, ranged between 30–149 µg/m³ and 24.4–460 µg/m³ respectively. The study infers that urban areas, especially those with frequent vehicular traffic and traffic congestion, had comparatively high RSPM exceeding the Indian prescribed standards (60 µg/m³). Emission inventory estimated for current vehicle strength showed that about 840 000 kg of particulate matter was emitted during 2001. Wind speed negatively correlated with RSPM, while it was positively correlated with NRSPM. Temperature had a negative correlation with RSPM values.     

Measurement of radioactivity levels of the Sirt gulf,Libya

The paper presents the results of measurements on air and soil samples collected for their natural and artificial radioactivity content. The radionuclides studied under this programme are ⁷Be and ¹³⁷Cs. Average activity concentrations in surface air of ⁷Be and ¹³⁷Cs were found to be 1920 and 2.1 μBq m^‐3, respectively. ¹³⁷Cs activity concentration in surface soil is found to be 450m Bq kg^‐1. Estimated effective doses to adult from inhaled ⁷Be and ¹³⁷Cs were found to be 1 and 0.13 nSvy^‐1, respectively.

The average outdoors absorbed dose rate in air, 1 m above the ground level was found to be (48 ± 4.0 nGy h^‐1), based on the analysis of thermoluminescence dosimeters data collected.     

Alternativen zur vereinfachten Bemessung von Einzelstützen?

Alternative simplified Design Procedures for isolated Columns? The simplified 2^nd order analysis for isolated compression members with nominal stiffness as in Eurocode 2 and the transformation of the non‐linear 2^nd order analysis to a modified cross section design are dealt by example of a slender cantilever column with biaxial bending.