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Information on the implementation of continuous renal replacement therapy (CRRT) in pediatric intensive care units (PICUs) is limited. We investigated the real-world practice of this therapy in Japan.We conducted a cross-sectional survey of 26 hospitals with PICUs in Japan. One physician per hospital responded to the questionnaire.Fewer than half of the hospitals followed the CRRT practice guidelines; treatment options were often selected at a physician's discretion. PICUs varied widely in continuous renal replacement settings, circuit priming methods, frequency of circuit exchange, and policies for using CRRT in sepsis. Only two anticoagulants were used: nafamostat mesylate and unfractionated heparin. Most units did not change the nutritional dosage according to CRRT use. Many facilities were proactive concerning rehabilitation.Nafamostat-centered anticoagulation management was unique to Japan. Our results may help identify areas where additional clinical studies are needed to standardize CRRT practice.

This paper presents the results of an experimental investigation on the performance of half-scale, unbonded, post-tensioning, precast concrete walls subjected to fully reversed cyclic loads. Moreover, this paper discusses the damage progression and failure mechanism of each specimen, associated with their construction details (damper types and confinement details of the boundary elements). Five isolated walls were tested, each consisting of precast concrete panels joined only by unbonded post-tensioning strands. The bottom joint of the walls featured two kinds of dampers: Three specimens had mild steel reinforcement, crossing the bottom joint, and the other two specimens had external replaceable hysteretic dampers, attached to the wall sides. Different types of confinement details at the boundary elements were used among the specimens. Steel fibers were mixed into the concrete of one specimen. The prestressing load ratio was 0.05 in most of the specimens. An additional axial load of 468.5 kN was applied to each specimen (additional axial load ratio of about 0.04), before any lateral loading. Quasi-static, displacement-controlled loads were applied to the specimens until a significant strength reduction was observed. Although only moderate axial loads were applied, most of the specimens sustained drifts above 3% while maintaining their lateral strength, gravity load stability, and self-centering. A better performance was observed in the specimens with external dampers, with drifts above 4%, less residual drifts and less cover concrete spalling, particularly in the specimen with steel fibers. The external dampers were very effective in dissipating energy before fracture, until 3% drifts. On the other hand, the specimens with internal dampers sustained unexpected damage at their bottom joint, after reaching their peak strength. For instance, the gravity load-carrying capacity of one specimen with internal dampers was compromised after 4% drifts. Then, the use of external replaceable dampers provided higher performance and post-earthquake recovery for unbonded post-tensioned precast walls. Additional design recommendations are provided based on the test results. Keywords: Shear walls; Precast concrete; Post-tensioning; Seismic dampers; Self-centering system; Energy dissipation; Hybrid walls.

The latest version of the Standard for Structural Calculation of Reinforced Concrete Structures, published by the Architectural Institute of Japan in 2010 [1], allows the design of shear walls with rectangular cross sections in addition to shear walls with boundary columns at the end regions (referred to here as “barbell shape”). In recent earthquakes, several reinforced concrete (RC) shear walls were damaged by flexural failures through concrete compression crushing accompanied with buckling of longitudinal reinforcement in the boundary areas. Damage levels have clearly been shown to be related to drift in structures; this is why drift limits are in place for structural design criteria. A crucial step in designing a structure to accommodate these drift limits is to model the ultimate drift capacity. Thus, in order to reduce damage from this failure mode, the ultimate drift capacity of RC shear walls needs to be estimated accurately. In this paper, a parametric study of the seismic behaviour of RC shear walls was conducted using a fibre-based model to investigate the influence of basic design parameters including concrete strength, volumetric ratio of transverse reinforcement in the confined area, axial load ratio and boundary column dimensions. This study focused on ultimate drift capacity for both shear walls with rectangular sections and shear walls with boundary columns. The fibre-based model was calibrated with experimental results of twenty eight tests on shear walls with confinement in the boundary regions. It was found that ultimate drift capacity is most sensitive to axial load ratio; increase of axial load deteriorated ultimate drift capacity dramatically. Two other secondary factors were: increased concrete strength slightly reduced ultimate drift capacity while increased shear reinforcement ratio and boundary column width improved ultimate drift capacity.

In order to use a damaged building continuously after earthquake, owners and/or stakeholders need to understand residual seismic capacity of the building. In Japan, a method to evaluate residual seismic capacity for damaged buildings had been developed. In order to evaluate residual seismic capacity of damaged building, the damage level of structural elements should be evaluated properly. This paper presents the results of damage analysis based on experimental data obtained from a full-scale static loading test [1] on a five-story reinforced concrete building tested at Building Research Institute. The damage rating for the specimens evaluated by the residual seismic capacity concept [3] was ”Moderate” or ”Heavy” at 0.5% and 1% building drift angle despite the structure maintaining horizontal load carrying capacity. This implies that the applied method gives a conservative result for ductile buildings, such as relatively new moment resisting frames designed after 1981. In order to apply the method used in this paper to new buildings, the damage evaluation method for structural elements should be advanced more in the future.

This paper proposes and validates a type of external replaceable hysteretic dampers to be mainly applied to unbonded post-tensioned (UPT) precast walls. The main aim of the proposed damper was to provide the UPT walls with large energy dissipation without significant buckling. To evaluate the efficiency of these dampers, a cyclic test was conducted. The damper specimens consisted of a mild steel round bar with a reduced diameter over a fused length and an additional threaded length at each side, for installation purposes. Moreover, a round steel tube was installed over the fused length and filled with grout to delay the buckling. The proposed dampers, with different geometries and conditions, were subjected to cyclic loads to evaluate their deformation capacity and fracture mechanism. The specimens displayed a regular and stable hysteretic curve until strains of 9%, after which a flexural buckling was observed at the ends of the fused length. However, this flexural buckling did not affect the energy-dissipating capacity in any specimen. Consequently, this type of damper is considered suitable for applications in self-centering rocking walls. Furthermore, the proposed dampers fractured by a combination of low-cycle fatigue and excessive rotations at the transition length. In addition to the experimental validation, an extensive numerical investigation was conducted on the proposed damper to complement the experimental data and to provide analytical tools for design.

Reinforced concrete (RC) coupled walls are extensively used as the seismic-resistant structural system of tall buildings in high seismic zones. In RC coupled wall systems, the coupling beams are typically designed and detailed to dissipate energy through large inelastic responses to meet the expected seismic performance under moderate-to-strong earthquakes. However, costly excessive repair or even complete demolition caused by the considerable damage in conventional RC coupling beams is usually inevitable. Such disadvantage of RC coupling beams has increased the interest on replaceable steel coupling beams, which can isolate the damage concentrated in the fuses; thus, these beams are expected to be replaced after a strong earthquake. However, replacing these beams in practice is difficult if considerable residual deformation exists in these replaceable fuses. Therefore, seismic resilience cannot be explicitly guaranteed. For this reason, this study proposes a novel self-centering (SC) steel coupling beam that incorporates superelastic shape memory alloy (SMA) bolts and steel angles. The SC steel coupling beam is composed of two elastic beam segments and one rocking segment. Elastic beam segments are designed by steel beams that connect to the RC walls at both ends of the coupling beam, whereas the rocking segment located in the middle of the coupling beam is controlled by the SMA bolts and steel angles. Two ingenious shear keys are designed between the elastic beam segments and the rocking segment; these shear keys help the SC coupling beam to exhibit centerline-rocking behavior that is free from beam elongation. The working principle of the novel SC steel coupling beam is described first. Then, the cyclic responses of the SMA bolt and the steel angle, which are the two core components in the SC steel coupling beam, are investigated. The seismic performance of the SC steel coupling beam is computationally investigated in consideration of the effects of steel angles and the prestrain in the SMA bolts. Results show that the proposed SC steel coupling beams exhibit excellent SC capability and energy dissipation. Most damage is isolated in the steel angles, which can be easily and rapidly inspected or replaced after earthquakes without operation interruption. Importantly, beam elongation is almost eliminated under cyclic loading. With these advantages, the SC steel coupling beam can provide a promising solution for high-performance coupled wall systems.

This paper presents an experimental and numerical study on a novel brace which is curved and partially strengthened by induction heating technology (induction-heated curved brace, IHCB). Induction heating, comprised of heating and quenching processes, is an advanced technology to raise steel material strength to 2–3 times. Because of the partial strengthening, the untreated region yields first while the induction-heated region is still elastic before larger deformation, so the post-yield stiffness of the whole brace increases. Besides, the initial curved deformation along the brace length, which is due to the uneven heating, is also flexibly employed to delay the yielding behavior and stabilize the compressive behavior. Tensile coupon tests and Vickers hardness tests on the untreated normal-strength specimens and induction-heated high-strength specimens show that the induction heating technology effectively improves the material strength to 2.2–2.6 times. Cyclic loading tests on CBB (conventional buckling brace) and IHCB series show that under tension, IHCBs show approximately 57% lower initial stiffnesses compared to that of CBB but reach the yield loads at the cycle twice as large as that of CBB owing to the initial deformation. After yielding, although the stiffness of CBB dramatically drops to 0.9% to its initial stiffness, IHCBs succeed to maintain higher post-yield stiffnesses, of which the ratios to their initial stiffnesses are larger than 30%. Under compression, IHCBs show the smooth transition into flexural behaviors without apparent buckling behaviors, and the stable compressive loads (the load at −0.5% axial strain) become 1.49 and 1.67 times larger than that of CBB. The data obtained from the strain gauges and displacement transducers show that the strain and transverse deformation of IHCBs are uniformly distributed along the brace length rather than locally concentrated at the limited region as seen in CBB. The numerical analysis conducted by ABAQUS and the proposed design equations capture the experimental results well.

Induction heating (IH) is an advanced technology to increase the strength of the steel material up to 2 to 3 times. This research proposed an innovative reinforcement method on the steel beam with web opening, which made full and flexible use of the IH technology to partially strengthen the region around web opening. First, Vickers hardness tests were conducted to investigate the IH effect, and it showed that the hardness of induction-heated region (IH region) was improved to 1.88 times compared to the untreated normal-strength region. Then, the monotonic loading tests on four kinds of steel beams with normal section without web opening, non-reinforced section, plate-reinforced section, and IH-reinforced section were conducted to figure out the structural performance. The apparent reduction of the load resistance by 29% ~ 34% was observed on the non-reinforced beam compared to the normal beam. Plate and IH reinforcements were proved to be effective to ensure the load resistance, of which the ratios to the normal one were 1.19–1.28 and 0.85–0.86, respectively, and maintain the great deformation capacity. Although the lower ductility of the IH region eventually led to the cracking at the hole edge of IH-reinforced beam at relatively large displacement, the dispersion of the strain concentration around the web opening of IH-reinforced beam was successfully observed by the image data processing system. Last, several equations base on the SCI design method were proposed to capture the experimental results.

Induction heating is an advanced technology to strengthen the selected region of steel materials. Recent advancement of the new treatment technique to partially strengthen large-scale steel components opens new research areas for civil engineering applications. This research explores the development of an innovative type of braces with the I-shaped section partially strengthened by induction heating. Therefore, when the normal-strength region of the brace enters the plastic stage, the induction-heated region can remain elastic before large deformations. This paper presents the design concept, numerical analysis, and the preliminary experiments on the proposed induction-heated braces, and finally clarifies the mechanism. The analysis results indicate that the induction-heated length and width greatly improve the tensile performances, and the larger induction-heated length relocates the hinge region after buckling, which is potential to stabilize the compressive behavior. The tensile coupon test results show that the yield strength and the tensile strength of the induction-heated region are raised up to 1.23 and 1.40 times of these of the normal-strength region. The preliminary experiments show that the proposed induction-heated braces succeed in achieving better tensile performances as well as reducing strain concentrations at the brace middle. However, the buckling loads of the induction-heated brace specimens are lower mainly due to the initial imperfections resulted from the induction heating process.

The objective of the present study is to contribute to the understanding of the seismic behavior and performance of reinforced concrete flexure-dominated walls when their boundaries are sub...

We focused on the basic adsorption properties of two types of cations, viz., 1-methoxymethyl-1-methylpyrrolidinium (MMMP) and 1-ethyl-3-methylimldazolium (EMI), on graphene, as a first step in investigating the properties of carbon electrodes in an electric double layer capacitor. To clarify the basic adsorption properties, we used first principles calculation based on the density functional theory with the generalized gradient approximation for the exchange-correlation energy. We investigated the electrical dipole moment formed between the cations and graphene and found that electric dipole moment per cation formed by MMMP is larger than by EMI. In addition, we found that intramolecular bindings of MMMP are stronger than those of EMI. Based on these results, we conclude that MMMP is more suitable as the material for electric double layer capacitor than EMI.

The purpose of this paper is to model mechanical properties of prestressing strand at elevated temperature for estimating the strength and deflection of prestressed concrete members during fire and/or after fire. Prestressing strands(SWPR7BL) of 12.7 mm in diameter were used as test coupons. Tensile tests on prestressing strands at elevated temperatures were conducted to investigate mechanical properties such as yield strength, Young's modulus and creep strain. Reduction in yield strength, Young's modulus and stress-strain curves at elevated temperature were formulated. Creep tests were conducted on prestressing strands. The initial stress applied was 70% of the yield strength. The maximum creep strain was as large as 545 microns at 250°C. Creep behavior of presstressing strands was approximated by a numerical formula proposed by Norton and Bailey. Using the formula together with time-hardening rule, an estimation method of relaxation of prestressing steel at high temperatures was proposed.

In order to investigate and clarify the characteristics of the friction damper with variable resistances, a total of four dynamic loading tests were conducted. The primary factors that influence the hysterestic properties of the damper were analyzed. The experimental results have indicated that the damper can apply two levels of friction resistance stably. The mechanism for the variance in the stiffness observed while the friction resistance of the damper was shifting from the lower level to the higher one was also discussed. Based on the results of experiments and discussion, an analytical cyclical model which can simulate the test results exactly was proposed.

Seven half-scale post-tensioned precast concrete beams were tested under anti-symmetrical flexure. The experimental parameters were shear span ratio and shear reinforcement ratio. Multi-strands and high strength shear reinforcement with nominal yield strength of 785 MPa were used as post-tensioning steel and shear reinforcement, respectively. Yielding of shear reinforcement was not observed in any of the specimens. The flexural capacity evaluated by the ACI rectangular concrete stress block with plane section assumption agreed well to the experimental results. The shear capacity was estimated by the design equation 71.2a in the AIJ Standard for Structural Design and Construction of Prestressed Concrete Structures. The experimental results collected by literature survey to past research revealed that shear failure modes could be related to each of the experimental parameters (shear span ratio, shear reinforcement strength and shear reinforcement ratio).

Ten 1/3-scale precast prestressed concrete columns under anti-symmetrical loading were tested. Experimental parameters were axial load level, prestressing force level, shear reinforcement ratio and grouting. The flexural capacities were evaluated by the ACI equivalent rectangular stress block and the plane section assumption. The evaluated results agreed well to the test results. An evaluation method of column shear strength based on the shear-friction model was proposed. One specimen lost its axial load capacity by shear failure, which could be predicted by the method. However, an appropriate value for the shear-friction factor μ should be discussed further. Load-deformation curves were analytically derived by specifying the decompression moment and the maximum load carrying capacity.

Recent years, three-dimensional magnetotelluric (MT) inversion is widely used in geophysical structural surveys. In this paper, we show how to galvanic distortion would influence to 3-D MT inversion results, and would like to propose an improvement of model covariance matrix which could deal the galvanic distortion. For accommodating the galvanic distortion effects, we first simulate a set of synthetic MT response for some models and then add the distortion effects that are a function of observation locations. We applied WSINV3DMT as an inversion method to these synthetic MT responses. As a result, we confirmed distinct differences between 3-D MT inversion results depending on the degree of galvanic distortion. When we applied WSINV3DMT with the modified model covariance matrix, we obtained better inversion result. Based on these numerical experiments, we conclude that the galvanic distortion should be considered and be dealt with in the inversion.

In this research, we show the effects of static distortion by heterogeneous surface in 3-D MT inversion results, and propose an improved 3-D MT inversion method that can remove the effects of static distortion. We use WSINV3DMT (Siripunvaraporn et al., 2005)1 to estimate synthetic MT response and obtain inversion results. First we confirmed 3-D MT forward calculation can express static distortion on MT response. Second we applied WSINV3DMT to synthetic some MT responses that are basically same, but some false resistivity anomalies are imaged due to the distortion. As a result we conformed distinct difference between 3-D MT inversion results. We also the improved 3-D MT inversion code based on WSINV3DMT. Based on our results, we suggest that this improved inversion can effectively express the distortion as heterogeneous surface layer, and can give us more reliable resistivity structure.

Typical damages to reinforced concrete buildings, both by the ground motions and the tsunami waves, are outlined in this section. The report herein is based primarily on the field survey of the AIJ members and collected through the members of the Reinforced Concrete Steering Committee of AIJ. The typical damages to reinforced concrete buildings are described below through the reports on the buildings selected and available for detailed survey. The damage reports below are translated selectively from the Chap. 6, Sect. 6.2 of AIJ report in Japanese version, which contains more photos and figures, especially on the structural plans as well as the damage rate evaluation of members. The reports on the buildings below are arranged as from the Japanese version: (1) school buildings located from north to south (Iwate, Miyagi, Fukushima and Kanto areas), (2) government offices, (3) residential buildings.

Calculations of the maximum compressive load and the mean crush load were made for various types of vehicle structural members. Sheet metal members with closed-hat section were chosen as a basic type by reason that these contributed to major collision energy absorption in the case of cars with unibody construction. Correlations between the static compressive loads and the dynamic compressive loads for these members were determined experimentally by the stress-strain relationship including strain rate sensitivity. Comparisons were made between the results of calculation by the mathematical model using these empirical equations and the experimental results for the crush characteristics of the members and the vehicle structures in collision.

THE POSTCOLLISION MOTION STARTS IMMEDIATELY UPON COMPLETION OF A COLLISION IMPACT WHERE THE VEHICLES OBTAIN NEW SETS OF VELOCITIES THROUGH AN EXCHANGE OF MOMENTUM. SIMILITUDE WITH MODEL STUDY AND FULLSCALE AUTOMOBILE EXPERIMENTS INDICATE THAT THE POST-COLLISION TRAJECTORY IS ESSENTIALLY A PLANE MOTION, GOVERNED BY INERTIA AND TIRE FRICTION. TRAJECTORIES DEPEND ON MANY PARAMETERS (SUCH AS TIRE FRICTION COEFFICIENT, FRONT WHEEL STEERING ANGLE, VEHICLE GEOMETICS, AND WHETHER WHEELS ARE LOCKED OR FREE TO ROTATE) BUT NOT ON THE VEHICLE WEIGHT. THEORETICAL COMPUTATION OF TRAJECTORIES ARE COMPARED WITH EXPERIMENTS. /AUTHOR/